Dissertations / Theses: 'Algal isolation'

1

Afolayan, Anthonia Folake. "Isolation and characterization of antiplasmodial metabolites from South African marine alga." Thesis, Rhodes University, 2008. http://hdl.handle.net/10962/d1003063.

Full text

Abstract:

Malaria is one of the three most deadly diseases in Africa. Although there are available treatments, their efficacy has been greatly reduced over the past two decades due to the development of resistance to currently available drugs. This has necessitated the search for new and effective antimalarial agents. This project approached the search for new antimalarial compounds in two ways: (i) by screening natural products isolated from marine algae against the Plasmodium parasite and (ii) by modification of selected isolated active compounds to target 1-deoxY-đ-xylulose 5-phosphate reductoisomerase (DXR), an enzyme found in the nonmevalonate isoprenoid biosynthetic pathway of Plasmodium Jalciparum. It was envisaged that such a compound would exhibit dual action on the Plasmodium parasite. Extracts obtained from 22 marine algae were prefractionated by solvent partitioning and were screened for anti plasmodial activity against the chloroquine sensitive (CQS) P. Jalciparum D 10 strain. Overall, 50% of the algae screened produced at least one crude fraction with activity against P. Jalciparum. Extracts of the algae Sargassum heterophyllum, Plocamium cornutum, Amphiroa ephedrea and Pterosiphonia cloiophylla gave the most promising results. Fractionation of S. heterophyllum afforded three tetraprenyltoluquinols (3.1, 3.2 and 3.5) and an all-trans-fucoxanthin (3.6). Three new compounds (4.5, 4.6 and 4.7) and two known halogenated monoterpenes (4.1 and 4.4) were isolated from P. cornutum. Each of the isolated compounds from both S. heterophyllum and P. cornutum showed antiplasmodial activity with IC₅₀ values ranging from 2.0 - 15.3 μM for S. heterophyllum and 13 - 230 μM for P. cornutum. Attempts to synthetically modify halogenated monoterpene 4.4 by dihydroxylation and phosphorylation in order to inhibit the DXR enzyme was unsuccessful. However, the hemiterpene analogue (5.42) of the halogenated monoterpenes was successfully phosphorylated and dihydroxylated to give compound 5.45 which showed promising activity against DXR. The result obtained indicated that the proposed phosphorylation and dihydroxylation of the halogenated monoterpene 4.4 would result in the synthesis of a potent DXR inhibitor and therefore a potential antimalarial agent with dual mode of action on the Plasmodium parasite.

APA, Harvard, Vancouver, ISO, and other styles

2

Jorge, Ricardo Ferreira. "Isolation and structural characterization of fucoidans from the brown algae Fucus vesiculosus." Master's thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/15669.

Full text

Abstract:

Mestrado em Biotecnologia - Biotecnologia Molecular agricultural, pharmaceutical, cosmetic or bioenergy applications. They contain bioactive compounds, namely, polysaccharides Fucoidan. These polysaccharides are mainly constituted by fucose residues and sulfate esters, and have been reported to possess a broad variety of bioactivities, such as anticoagulant, anti-thrombotic, anti-inflammatory, anti-tumor, antiviral and antioxidant. In this work, the fucoidans from brown seaweed Fucus vesiculosus from “Ria de Aveiro” were isolated and characterized in order to add value to this natural resource of the region. The polysaccharides from the algae were extracted with hot water and fractioned by ethanol precipitation and calcium chloride salts. They were further purified by using anion-exchange chromatography, allowing to separate the neutral polysaccharides (laminaranas) from those negatively charged (sulfated fucoidans and alginate). The purified polysaccharides showed high content of fucose (41 mol%) and sulfates (50 mol%), having also galactose residues (6 mol%), which confirm the presence of only sulfated fucoidans. Glycosidic linkages analysis show the presence of high amounts of terminal fucose (25%) and (1→3,4)-Fuc (26%), allowing to infer that the fucoidans were highly branched. These fucoidans are composed also by (1→2)-Fuc (14%) and (1→3)-Fuc linkages (10-16%). In this work it was also tested an alternative extraction technology, the microwave hydrodiffusion and gravity system, where it was possible to extract sugars, although in low yields. However, this methodology allowed to extract polysaccharides, constituted mainly by fucose and uronic acids, as well as mannitol, without the need to add any solvent, obtaining at the end the dry alga. The current work allowed to characterize the structure of the fucoidans isolated from “Ria de Aveiro” F. vesiculosus. The presence of high content of sulfate residues and the high branch degree of the purified fucoidans allow to infer that these polysaccharides could have potential to be studied for biomedical applications, according to their biological activities. As algas castanhas fazem parte de um grupo de organismos cuja utilização tem vindo a crescer nas áreas da alimentação, agricultura, farmacêutica, cosmética e bioenergia. Estas algas são constituídas por diversos compostos com atividades biológicas destacando-se as fucoidanas. Estas são polissacarídeos compostos maioritariamente por fucose e ésteres de sulfato, apresentando várias atividades biológicas, tais como anticoagulante, anti trombótica, anti-inflamatória, anti-tumoral, antivírica e antioxidante. Neste trabalho foram isoladas e caracterizadas as fucoidanas da alga castanha, Fucus vesiculosus, da Ria de Aveiro de forma a potenciar este recurso natural da região. Os polissacarídeos constituintes da alga foram extraídos com água quente e fracionados por precipitação em etanol e sais de cloreto de cálcio. Os polissacarídeos foram purificados utilizando uma cromatografia de troca aniónica, permitindo separar os polímeros neutros (laminaranas) dos carregados negativamente (fucoidanas sulfatadas e alginatos). Os polissacarídeos purificados eram constituídos por fucose (41 mol%) e sulfatos (50 mol%), contendo também galactose (6% mol), comprovando a presença de apenas fucoidanas sulfatadas. A análise das ligações glicosídicas, mostrou a presença de fucose terminal (25%) e (1→3,4)-Fuc (26%), demonstrando que as fucoidanas eram muito ramificadas. Outras ligações presentes são (1→2-)-Fuc (15%) e (1→3)-Fuc. Neste trabalho foi também testada uma tecnologia de extração alternativa, o sistema de micro-ondas de hidro-difusão e gravidade, onde foi possível extrair alguns açúcares, embora com rendimentos reduzidos. Esta metodologia permitiu extrair os polissacarídeos, constituídos por fucose e ácidos urónicos, e também manitol sem necessidade de adicionar qualquer solvente e permitindo obter a alga seca no final da extração. Este trabalho permitiu caracterizar estruturalmente as fucoidanas isoladas do F. vesiculosus da Ria de Aveiro. A elevada quantidade de ésteres de sulfato e o elevado grau de ramificação sugere que estes polissacarídeos têm potencial para serem estudados em relação às suas atividades biológicas para serem usados em aplicações biomédicas.

APA, Harvard, Vancouver, ISO, and other styles

3

Fakee, Jameel. "The isolation and characterisation of secondary metabolites from selected South African marine red algae (Rhodophyta)." Thesis, Rhodes University, 2013. http://hdl.handle.net/10962/d1001472.

Full text

Abstract:

Secondary metabolites from natural sources are fast growing as popular drug leads. The structural novelty and favourable biological activity that these compounds display contribute to their popularity as drugs of the future. Examples of such compounds include the potent anticancer drug paclitaxel isolated from the bark of a yew tree as well as the more commonly known analgesic aspirin which stems from the bark of the willow tree. The biological activities exhibited by these secondary metabolites are vast and range from antimicrobial to anticancer activity to mention but a few. As a result, the isolation of novel compounds from natural sources is on the rise. The South African seaboard is home to a wealth of various marine algal species which produce fascinating secondary metabolites. For example, Portierria hornemanii was shown to produce halomon, a halogenated monoterpene which has displayed promising cytotoxic activity. This study thus focused primarily on pursuing novel compounds from three endemic South African marine algal species which have never been analysed previously from a chemical perspective. These are Plocamium rigidum (Bory de Saint-Vincent), Laurencia natalensis (Kylin) and Delisea flaccida (Suhr) Papenfuss. Four known compounds and one new halogenated monoterpene, (2E,5E,7Z)-8-chloro- 7-(dichloromethyl)-4-hydroxy-3-methylocta-2,5,7-trienal, were isolated from Plocamium rigidum. The breast cancer (MCF-7 cell line) inhibitory activity for these compounds was assessed and it was observed that an increase in the lipophilic nature of the compounds produced more favourable IC50 values. A pre-cursor to bromofucin type compounds, cis-laurencenyne, was isolated from Laurencia natalensis, as well as a new acetoxy chamigrane type compound, 4-bromo- 3,10-dichloro-7-hydroxy-3,7,11,11-tetramethylspiro [6.6] undec-1-yl acetate. Delisea flaccida was seen to contain two known bromofuranone type compounds isolated as an isomeric mixture, 1-[(5Z)-4-bromo-5-(bromomethylidene)-2-oxo-2,5- dihydrofuran-3-yl] butyl acetate and 1-[(5E)-4-bromo-5-(bromomethylidene)-2- oxo-2,5-dihydrofuran-3-yl]butyl acetate. These compounds are famous for their ability to inhibit bacterial biofilm production and they have been isolated before from an Australian Delisea spp Adobe Acrobat 9.53 Paper Capture Plug-in

APA, Harvard, Vancouver, ISO, and other styles

4

Almohsen, Jasem Saleh H. "Isolation and characterisation of halotolerant bacteria and algae and their potential for biofuel production." Thesis, University of Sheffield, 2014. http://etheses.whiterose.ac.uk/6406/.

Full text

Abstract:

The first aim of the project was to isolate, identify and characterize salt tolerant bacteria from river and pond water. This aim was achieved by the isolation of the salt tolerant bacterium Enterococcus amnigenus from water samples taken from Weston Park pond and by the isolation of the salt tolerant bacterium Pseudomonas fluorescens from a dew pond in the Derbyshire Peak District. E. amnigenus in common with many enterococci, is a potential pathogen, but it also has uses in industry as a producer of bacterial cellulose. P. fluorescens is a ubiquitous organism found in marine and soil environments and has been well characterized as an important biofilm-forming organism and as a rhizobacterium. The second aim of the project was to isolate salt-tolerant microalgae from the fresh water Weston Park pond and this was successfully achieved by isolating and identifying two algal species - the diatom Navicula pelliculosa and the green alga Chlorella sp. Initial work measuring total lipid concentrations suggested that Navicula was the most promising organism for biofuel production due to having a total lipid concentration of around 20%. Further characterization of Navicula was undertaken to investigate its suitability for biofuel production. It was shown to grow under conditions of high pH and high salinity, making it a candidate species for growth in outdoor raceway ponds. Experiments using Nile Red fluorescence to measure neutral lipid production indicated that stress conditions (high salinity or high pH) could increase the neutral lipid accumulation by Navicula cells. To grow in high salinity (up to 0.8 M NaCl), Navicula cells must balance the external osmotic potential by accumulating a compatible solute within the cells. NMR analysis showed that the compatible solute accumulated by Navicula is glucosylglycerol, which is not normally found in diatoms.

APA, Harvard, Vancouver, ISO, and other styles

5

Knott, Michael George. "Isolation, structural characterisation and evaluation of cytotoxic activity of natural products from selected South African marine red algae." Thesis, Rhodes University, 2012. http://hdl.handle.net/10962/d1015460.

Full text

Abstract:

The medicinal chemistry of selected marine algae indigenous to South Africa was investigated. Following the isolation and characterisation of a number of new and known compounds, the associated in vitro cytotoxic profiles of these new compounds was investigated. Plocamium maxillosum yielded two new cyclic polyhalogenated monoterpenes which were characterised as 2E-chloromethine-4E-chlorovinyl-4-methyl-5-cyclohexen-1-one (2.1) and 2Z-chloromethine-4E-chlorovinyl-4-methyl-5-cyclohexen-1-one (2.2) on the basis of one and two dimensional NMR spectroscopic data and MS analysis. These compounds were also found to have good cytotoxic activity against breast cancer cell lines. Although these compounds are based on a regular monoterpene skeleton, they represent an uncommon feature not often seen in cyclic halogenated monoterpenes from marine algae. Plocamium robertiae yielded one new cyclic polyhalogenated monoterpene identified as 4,5- dibromo-5-chloromethyl-1-chlorovinyl-2-chloro-methylcyclohexane (2.6) and one known compound called 2,4-dichloro-1-chlorovinyl-1-methylcyclohexane-5-ene or Plocamene D (2.9). Portieria hornemannii was collected from Port Edward in Natal and yielded three new compounds, namely; 3Z-1,6-dibromo-3-(bromomethylidene)-2,7-dichloro-7-methyloctane (3.1), 1E,3Z-1,6-dibromo-3-(bromomethylidene)-7-chloro-7-methyloct-1-ene (3.2), 1Z,3Z- 1,6-dibromo-3-(bromomethylidene)-7-chloro-7-methyloct-1-ene (3.3), and one known compound, namely; 3S,6R-6-bromo-3-(bromomethyl)-3,7-dichloro-7-methyloct-1-ene (3.4). Compounds 3.1 and 3.2 showed no cytotoxic activity against breast cancer cells. Another Portieria hornemannii sample was collected from Noordhoek in the Eastern Cape, it yielded one known compound referred to as 3Z-6-bromo-3-(bromomethylidene)-2,7- dichloro-7-methyloct-1-ene (3.5), as well as one new compound called portieric acid A (3.6) or 5-bromo-2-(bromomethylidene)-6-chloro-6-methylheptanoic acid. Portieric acid A showed slight cytotoxic activity and also represents a new class of compound within the genus Portieria. The isolation of secondary metabolites from the South African red alga, Laurencia glomerata, yielded two known compounds; 7-hydroxylaurene (4.9) and cis-neolaurencenyne (4.12), as well as one chamigrane related compound (4.11). Laurencia flexuosa yielded one known compound called 3Z-bromofucin (4.13). Using 1H NMR, GC and molecular systematics, a novel method for identifying different species of Laurencia was also investigated.

APA, Harvard, Vancouver, ISO, and other styles

6

Gopalakrishnan, Kishore. "Isolation, characteristation and screening of New Zealand alpine algae for the production of secondary metabolites in photobioreactors." Thesis, University of Canterbury. Chemical and Process Engineering, 2015. http://hdl.handle.net/10092/10668.

Full text

Abstract:

This inter-disciplinary thesis is concerned with the production of polyunsaturated fatty acids (PUFAs) from newly isolated and identified alpine microalgae, and the optimization of the temperature, photon flux density (PFD), and carbon dioxide (CO2) concentration for their mass production in an airlift photobioreactor (AL-PBR). Thirteen strains of microalgae were isolated from the alpine zone in Canyon Creek, Canterbury, New Zealand. Ten species were characterized by traditional means, including ultrastructure, and subjected to phylogenetic analysis to determine their relationships with other strains. Because alpine algae are exposed to extreme conditions, and such as those that favor the production of secondary metabolites, it was hypothesized that alpine strains could be a productive source of PUFAs. Fatty acid (FA) profiles were generated from seven of the characterized strains and three of the uncharacterized strains. Some taxa from Canyon Creek were already identified from other alpine and polar zones, as well as non-alpine zones. The strains included relatives of species from deserts, one newly published taxon, and two probable new species that await formal naming. All ten distinct species identified were chlorophyte green algae, with three belonging to the class Trebouxiophyceae and seven to the class Chlorophyceae. Comparative study between the distribution of algae at Canyon Creek and Mount Philistine, another alpine region in New Zealand where algal distribution was studied in detail, revealed that algal distribution patterns in the New Zealand alpine zone are complex, with some taxa apparently widely distributed and others range restricted or rare (with the caveat that very few sites have been studied in detail). At least some of the differences between the two sites could be accounted for by geographic differences, resulting in contrasting environmental conditions such as rainfall. As hypothesized, alpine strains isolated from the Canyon Creek were rich in PUFAs. Eight among the ten strains have PUFA proportions higher than monounsaturated fatty acids and saturated FAs. In a comparison of FA profiles of Scenedesmaceae species from a hot environment (Algerian Sahara) with the Scenedesmaceae species from Canyon Creek, the latter revealed a much greater degree of unsaturation. In addition, the Canyon Creek strains contained some FAs (such as docosapentaenoic acid, DPA) that were absent from Saharan strains. Among the strains from Canyon Creek Lobochlamys segnis LCR-CC-5-1A was selected for optimization experiments on the basis of growth kinetics, temperature response and FA composition, of which 60% of total FAs were PUFAs. Of that 60%, the α-linolenic acid (ALA) content was 46%. Two identical 1.5 Liter AL-PBRs were used for culturing Lobochlamys segnis LCR-CC-5-1A to study the effect of CO2 concentration, PFD and temperature on specific growth velocity, production of PUFAs, omega-3 FAs and, specifically, the concentration of ALA. The concentrations of CO2 examined in this research were 1.5, 3.0 and 4.5% in air. Similarly, the reponses of the strain to seven different PFDs, namely 38, 77, 115, 178, 210, 236 and 253 µmol m-2 s-1 and six different temperatures, 5, 10, 15, 20, 25 and 30οC, were analyzed. The maximum specific growth velocities (µmax) of the cultures were calculated from the experimental data and the cell production rate was calculated from fitting logistic growth models to these data; the two were compared by converting the former to the latter. The significance of the tested parameters was assessed using ANOVA and Tukey tests. The optimum conditions assessed at lab scale for maximum production of biomass, PUFAs and ALA were found to be a CO2 concentration of 3.0%, temperature of 20°C, and PFD of 178 µmol m-2 s-1. Increasing biomass production has the effect of maximizing PUFA production because there was no significant increase in concentration of PUFAs, omega-3 FAs, or ALA under levels of CO2, temperature, and PFD differing from those under which maximum growth occurred.

APA, Harvard, Vancouver, ISO, and other styles

7

Fish, Brendan Cormick. "Isolation and characterisation of lectins from marine algae, with particular reference to Plumaria elegans and Ptilota serrata." Thesis, University of Portsmouth, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328145.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Barreto, Michael. "Antimicrobial activity of macroalgae from Kwazulu-Natal, South Africa, and the isolation of a bioactive compound from Osmundaria serrata (Rhodophyta)." Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-09052005-095635/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Loveless, R. W. "Isolation and biochemical characterisation of lectins from selected marine algae, with particular reference to sub-species of Codium fragile." Thesis, University of Portsmouth, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355597.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Saboya, Jefferson Pablo de Sousa. "Isolation, partial characterization of lectins present in green seaweed Udotea flabellum ( J. Ellis & Solander ) M. A. Howe in 1904 and Codium isthmocladum Vickers 1905 ( CIL -3 ) and evaluation of toxicity and antibacterial activity." Universidade Federal do CearÃ, 2016. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=16412.

Full text

Abstract:

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico O estudo de lectinas de algas marinhas aponta para a possibilidade de se isolar substÃncias com caracterÃsticas Ãmpares, que poderiam contribuir para os estudos da aplicaÃÃo de substÃncias com atividades biolÃgicas nas Ãreas das ciÃncias biomÃdicas. O presente estudo constou da purificaÃÃo e caracterizaÃÃo parcial de duas novas lectinas presentes nas algas marinhas verdes Udotea flabellum, aqui denominada de UFL e da Codium isthmocladum, denominada de CiL-3, respectivamente. AlÃm da avaliaÃÃo da toxicidade em naÃplios de Artemia e das atividades antibacterianas de crescimento planctÃnico, formaÃÃo de biofilmes e a agregaÃÃo de bactÃrias Gram-positivas Staphylococcus aureus e S. epidermidis e a Gram-negativa Escherichia coli. O isolamento de lectinas foi obtido por uma combinaÃÃo de diferentes tÃcnicas de purificaÃÃo. UFL mostrou especificidade para eritrÃcitos de coelho tratados com enzimas proteolÃticas, tripsina e papaÃna. Aglutinou eritrÃcitos humanos do sistema ABO e nÃo foi inibida por aÃÃcares simples, apenas pelas glicoproteÃnas mucina de estÃmago de porco (PSM) e tiroglobulina. Exibiu uma Ãnica banda com massa molecular aparente de 60 kda e duas distintas bandas protÃicas com massa molecular de 29 e 20 kDa. TermoestÃvel, os valores mais altos de atividade hemaglutinante foram no pH 6, nÃo dependente de cÃtions divalentes, sem glicolisaÃÃes, atÃxica contra naÃplios de Artemia sp. NÃo foi capaz de inibir o crescimento planctÃnico e diminuir a biomassa do biofilme de S. aureus, no entanto, mostrou uma fraca inibiÃÃo para S. epidermidis, nÃo apresentou reduÃÃo significativa no nÃmero de cÃlulas viÃveis das bactÃrias Gram-positivas e tambÃm nÃo causou aglutinaÃÃo nas bactÃrias. No que diz respeito a lectina isolada de Codium, a atividade hemaglutinante da CiL-3 mostrou ser ativa apenas para eritrÃcitos de coelho tratados com enzimas proteolÃticas, nÃo sendo capaz de aglutinar eritrÃcitos de coelho nativo e humanos do sistema ABO, foi inibida pelo aÃÃcar simples rafinose e a glicoproteÃna mucina, apresentou como uma Ãnica banda de aproximadamente 20 kDa. Relativamente termoestÃvel, a atividade hemaglutinante foi mais elevada em pH 5, nÃo dependÃncia de cÃtions divalentes. Todas as lectinas isoladas de Codium isthmocaldum (CiL-1, CiL-2 e CiL-3) foram capazes de diminuir a biomassa do biofilme de S. aureus, somente a CiL-2 apresentou inibiÃÃo para S. epidermidis e foi capaz de apresentar reduÃÃo no nÃmero de cÃlulas viÃveis. Embora a CiL-3 nÃo tenha apresentado aglutinaÃÃo para as cÃlulas de Escherichia coli, a lectina foi capaz de aglutinar cÃlulas formadora do biofilmes de S. aureus e S. epidermidis. O estudo de lectinas de algas marinhas aponta para a possibilidade de se isolar substÃncias com caracterÃsticas Ãmpares, que poderiam contribuir para os estudos da aplicaÃÃo de substÃncias com atividades biolÃgicas nas Ãreas das ciÃncias biomÃdicas. O presente estudo constou da purificaÃÃo e caracterizaÃÃo parcial de duas novas lectinas presentes nas algas marinhas verdes Udotea flabellum, aqui denominada de UFL e da Codium isthmocladum, denominada de CiL-3, respectivamente. AlÃm da avaliaÃÃo da toxicidade em naÃplios de Artemia e das atividades antibacterianas de crescimento planctÃnico, formaÃÃo de biofilmes e a agregaÃÃo de bactÃrias Gram-positivas Staphylococcus aureus e S. epidermidis e a Gram-negativa Escherichia coli. O isolamento de lectinas foi obtido por uma combinaÃÃo de diferentes tÃcnicas de purificaÃÃo. UFL mostrou especificidade para eritrÃcitos de coelho tratados com enzimas proteolÃticas, tripsina e papaÃna. Aglutinou eritrÃcitos humanos do sistema ABO e nÃo foi inibida por aÃÃcares simples, apenas pelas glicoproteÃnas mucina de estÃmago de porco (PSM) e tiroglobulina. Exibiu uma Ãnica banda com massa molecular aparente de 60 kda e duas distintas bandas protÃicas com massa molecular de 29 e 20 kDa. TermoestÃvel, os valores mais altos de atividade hemaglutinante foram no pH 6, nÃo dependente de cÃtions divalentes, sem glicolisaÃÃes, atÃxica contra naÃplios de Artemia sp. NÃo foi capaz de inibir o crescimento planctÃnico e diminuir a biomassa do biofilme de S. aureus, no entanto, mostrou uma fraca inibiÃÃo para S. epidermidis, nÃo apresentou reduÃÃo significativa no nÃmero de cÃlulas viÃveis das bactÃrias Gram-positivas e tambÃm nÃo causou aglutinaÃÃo nas bactÃrias. No que diz respeito a lectina isolada de Codium, a atividade hemaglutinante da CiL-3 mostrou ser ativa apenas para eritrÃcitos de coelho tratados com enzimas proteolÃticas, nÃo sendo capaz de aglutinar eritrÃcitos de coelho nativo e humanos do sistema ABO, foi inibida pelo aÃÃcar simples rafinose e a glicoproteÃna mucina, apresentou como uma Ãnica banda de aproximadamente 20 kDa. Relativamente termoestÃvel, a atividade hemaglutinante foi mais elevada em pH 5, nÃo dependÃncia de cÃtions divalentes. Todas as lectinas isoladas de Codium isthmocaldum (CiL-1, CiL-2 e CiL-3) foram capazes de diminuir a biomassa do biofilme de S. aureus, somente a CiL-2 apresentou inibiÃÃo para S. epidermidis e foi capaz de apresentar reduÃÃo no nÃmero de cÃlulas viÃveis. Embora a CiL-3 nÃo tenha apresentado aglutinaÃÃo para as cÃlulas de Escherichia coli, a lectina foi capaz de aglutinar cÃlulas formadora do biofilmes de S. aureus e S. epidermidis.

APA, Harvard, Vancouver, ISO, and other styles

11

Nobre, Clareane Avelino Simplicio. "Isolation, purification and partial characterization of the primary structure of a ficobiliproteÃna from the red marine alga Hypnea musciformis (Wulfen) Lamouroux." Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=14214.

Full text

Abstract:

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico Seaweeds are a rich reserve of substances with biotechnological interest, among these substances it is possible to highlight the phycobiliproteins. These molecules are water-soluble proteins covalently linked to pigments with linear tetrapyrrole structure called bilin, also known as accessory pigment. Thus, the phycobiliproteins form a complex named phycobilisomes, which is a primary structure of light-gathering, showing photosynthetic function. These structures are found in red and Cyanophyceae seaweed. Phycobiliproteins isolated and purified, when structuraly analised, present subunits characterized as alpha, beta and gamma. These proteins can be used as colorants and stabilizers for food, markers of biomolecules, antioxidants and anti-inflammatory agents. In view of the importance of these molecules, this work aimed to isolate, purify and determine the partial primary structure of the beta chain phycobiliprotein present in the red marine algae Hypnea musciformis. The phycobiliprotein (HMp) was isolated by precipitation of proteins with ammonium sulphate and purified by ion-exchange chromatography. The polyacrylamide gel electrophoresis revealed that the HMp has two chains around 20 kDa and 22 kDa. The 22 kDa chain was excised from the gel and digested with proteolytic enzyme trypsin. The peptides from digestion underwent fragmentation in mass spectrometer. The generated fragments were used for sequencing peptides and have identified in databases. Primers were designed to amplify the beta chain gene bhmp from the genomic DNA of the algae. The amplified gene was sequenced and the tool Phred/Phrap/Consed processed the raw data. The final gene sequence has been translated to obtain the partial primary structure of bHMp. The translation resulted in a sequence with 87 amino acid residues and HMp presented identity with various phycoerythrins of red algae. As algas marinhas constituem uma rica reserva de substÃncia de interesse biotecnolÃgico, dentre essas substÃncias podemos destacar as ficobiliproteÃnas. Essas molÃculas sÃo proteÃnas solÃveis em Ãgua ligadas covalentemente a pigmentos com estrutura tetrapirrÃlica linear denominado bilina, tambÃm conhecido como pigmento acessÃrio. Dessa forma, as ficobiliproteÃnas formam um complexo denominado ficobilissomos, que constitui uma estrutura primordial de captaÃÃo de luz, apresentando funÃÃo fotossintÃtica. Essas estruturas sÃo encontradas nas algas marinhas vermelhas e cianofÃceas. FicobiliproteÃnas isoladas e purificadas, quando caracterizadas, apresentaram subunidades estruturais, como subunidades alfa, beta e gama. Quanto a suas aplicaÃÃes, essas proteÃnas foram utilizadas como corantes e estabilizantes de alimentos, marcadores de biomolÃculas, agentes antioxidantes e anti-inflamatÃrios. Tendo em vista a importÃncia destas molÃculas, este trabalho teve como objetivo isolar, purificar e determinar a estrutura primÃria parcial da cadeia beta de uma ficobiliproteÃna presente na alga marinha vermelha Hypnea musciformis. A ficobiliproteÃna (HMp) foi isolada atravÃs da precipitaÃÃo do extrato proteico com sulfato de amÃnio e purificada por cromatografia de troca iÃnica. A eletroforese em gel de poliacrilamida revelou que a HMp possui duas bandas proteicas em torno de 20 kDa e 22 kDa. A banda de 22 kDa foi excisada do gel e digerida com a enzima proteolÃtica tripsina. Os peptÃdeos oriundos da digestÃo foram submetidos Ã fragmentaÃÃo em espectrÃmetro de massas. Os fragmentos gerados foram utilizados para sequenciar os peptÃdeos e estes na identificaÃÃo de proteÃnas a partir dos bancos de dados existentes. A partir dessas informaÃÃes, iniciadores foram desenhados para amplificar o gene da cadeia beta da ficobiliproteÃna de Hypnea musciformis (bhmp) a partir do DNA genÃmico da alga. O gene amplificado foi sequenciado e os dados brutos foram processados pela ferramenta Phred/Phrap/Consed. A sequÃncia processada foi traduzida para obtenÃÃo da estrutura primÃria parcial de bhmp. A traduÃÃo resultou em uma sequÃncia de 87 resÃduos de aminoÃcidos e HMp apresentou identidade com diversas ficoeritrinas de algas vermelhas.

APA, Harvard, Vancouver, ISO, and other styles

12

Schroeder, Declan Cosmo. "Isolation and characterization of a β(1-4) agarase of an epiphytic bacterial pathogen, Pseudoalteromonas gracilis B9, of the red alga, Gracilaria gracilis". Doctoral thesis, University of Cape Town, 2001. http://hdl.handle.net/11427/4328.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Thürich, Johannes [Verfasser], Erika [Gutachter] Kothe, Philipp [Gutachter] Franken, and Alga [Gutachter] Zuccaro. "Isolation and characterization of novel biomolecules during the mutualistic interaction between Piriformospora indica and Arabidopsis thaliana / Johannes Thürich ; Gutachter: Erika Kothe, Philipp Franken, Alga Zuccaro." Jena : Friedrich-Schiller-Universität Jena, 2020. http://d-nb.info/1213348781/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Reddy, Priyanka, and saipriyanka@gmail com. "Studies in Marine Natural Products." RMIT University. Applied Sciencez, 2009. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20091023.091658.

Full text

Abstract:

The focus of this thesis was to study the chemotaxonomic relationship of selected southern Australian marine brown algae of the genera Cystophora and Sargassum. Consequently, this resulted in the isolation and structure elucidation of six new terpenoids from two southern Australian marine brown algae Cystophora moniliformis and Sargassum fallax together with 10 previously reported natural products. As a result of the re-isolation of these known secondary metabolites, updated and complete structural characterisation data could be provided for the first time for 7 of these compounds. Chemotaxonomic studies of Cystophora moniliformis resulted in the isolation of two new cyclic epimeric terpene diols moniliforminol A (3.25) and moniliforminol B (3.26), a new linear farnesyl acetone derivative (3.27) and the previously described terpenoids (3.19)-(3.24). This study also resulted in the first complete 2D NMR characterisation for compounds (3.21) to (3.24) as well as the first report of (3.24) occurring as a natural product. All structures were elucidated by detailed spectroscopic analysis with the relative configurations of (3.25) and (3.26) being established by selective 1D nOe NMR experiments. The proposed biosynthetic pathway for the above compounds has also been described. Chemical investigation of the Southern Australian marine brown alga Sargassum fallax resulted in the isolation of three new meroditerpenoids fallahydroquinone (4.8), fallaquinone (4.9) and fallachromenoic acid (4.10), together with the previously reported compounds sargaquinone (4.1) (isolated and identified in a mixture with sargaquinoic acid), sargahydroquinoic acid (4.2), sargaquinoic acid (4.3) and sargachromenol (4.11). As a result of this study the complete 2D NMR characterisation for sargahydroquinoic acid (4.2) and sargaquinoic acid (4.3) could also be reported for the first time. All structures were elucidated by detailed spectroscopic analysis. Sargahydroquinoic acid (4.2) and sargaquinoic acid (4.3) displayed moderate antitumour activity.

APA, Harvard, Vancouver, ISO, and other styles

15

Hadebe, Nontando. "Isolation and characterization of prebiotic oligosaccharides from algal extracts and their effect on gut microflora." Thesis, 2016. http://hdl.handle.net/10321/1754.

Full text

Abstract:

Submitted in partial fulfillment for the Degree of Master of Applied Sciences in Biotechnology, Durban University of Technology, Durban, South Africa, 2016. Prebiotics are defined as non-digestible oligosaccharides (NDOs) or polysaccharides (NDPs), which promote the growth of beneficial lactic acid bacteria in the colon. Algae are rich in polysaccharides and can be exploited as prebiotics for functional food ingredients to improve human and animal health. Currently, inulin is the most widely used ingredient in the prebiotics market, which is produced from live plants and requires expensive production processing. There is a vast repository of marine life with algae as a major source of nutrients. Therefore, this study provides an alternative source for prebiotic production and examines marine and freshwater algae that promote the growth of two strains of Lactobacillus delbrueckii subs. (Lactobacillus lactis and Lactobacillus bulgaricus) and one strain of Bifidobacterium spp. (Bifidobacterium longum). Monosaccharides of the oligosaccharide fraction of marine and freshwater algal extracts were investigated with the use of thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) after acidic hydrolysis of cell matrix polysaccharides. A total of fifty-five marine and freshwater aqueous algal extracts were assessed for their effect on the growth of L. lactis, B. longum and L. bulgaricus over a 96 hour period. Relative to the negative control, 34.5% algal extracts showed improved growth on one or more probiotic bacteria. The optimum time for maximum bacterial growth was noted at 48 h for all the tested aqueous algal extracts. Five marine and freshwater algal cultures (Spirulina platensis, Chlorococcum spp., Dunaliella salina, Scenedesmus magnus, Chlorella spp. and algal extract no. 48) from various aquatic environments in Kwa-Zulu Natal showed the best growth dynamics and demonstrated the greatest potential as sources of biomass for prebiotic production. These algal extracts were able to significantly increase the growth of at least one of the three probiotic bacteria (p < 0.05). Aqueous algal extract from S. platensis was regarded as the best algal source for prebiotics as it demonstrated a greater stimulatory effect on the growth of all three probiotic bacteria (L. lactis, B. longum and L. bulgaricus) compared to tested aqueous algal extracts and the inulin used as a positive control. The results obtained by HPLC for characterization confirmed TLC data, as xylose and galactose were detected by both chromatograms. These data indicated that xylose and galactose were present in aqueous algal extracts from S. magnus and S. platensis and galactose in aqueous algal extract no. 48. Xylose was most abundant in aqueous algal extracts from S. platensis (3mg/ml) and S. magnus (2.3mg/ml). In conclusion aqueous algal extracts from S. platensis, Chlorococcum, D. salina, S. magnus, Chlorella and algal extract no. 48 are potential sources for prebiotic production. Spirulina platensis extract was regarded as the best algal source. Xyose and galactose characterized by HPLC in algal extracts make up oligosaccharides that function as prebiotic compounds for stimulation of probiotic bacteria. There is a great scope for successful production of prebiotics from algal sources in South Africa. M

APA, Harvard, Vancouver, ISO, and other styles

16

Lin, Chi-Lei, and 林季磊. "Study on the Isolation and Oversulfation of Marine Algal Oligosaccharides and Evaluation on Their Biological Activities." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/02163736799223927371.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Dziwornu, Godwin A., Mino R. Caira, la Mare Jo-Anne De, et al. "Isolation, characterization and antiproliferative activity of new metabolites from the South African endemic red algal species Laurencia alfredensis." 2017. http://hdl.handle.net/10962/59963.

Full text

Abstract:

The marine red algae of the genus Laurencia have been widely studied for their structurally diverse and biologically active secondary metabolites. We report here the natural product investigation of the organic extract of a newly identified South African endemic species, Laurencia alfredensis. A sequence of column chromatography, preparative TLC and normal phase HPLC resulted in the isolation of eleven compounds comprising three labdane-type diterpenes (1-3), four polyether triterpenes (4-7), three cholestane-type ecdysteroids (8-10) and a glycolipid (11). Compounds 1-3, 5-8 and 10 have not previously been reported, while compound 9 is reported here for the first time from a natural source and the known compound 11 isolated for the first time from the genus Laurencia. The structural elucidation and the relative configuration assignments of the compounds were accomplished by extensive use of ID- and 2D-NMR, HR-ESI-MS, UV and IR spectroscopic techniques, while the absolute configuration of compound 1 was determined by single-crystal X-ray diffraction analysis. All compounds were evaluated against the MDA-MB-231 breast and HeLa cervical cancer cell lines. Compound 2 exhibited low micromolar antiproliferative activity (IC50 = 9.3 gM) against the triple negative breast carcinoma and compound 7 was similarly active (IC50 = 8.8 gM) against the cervical cancer cell line.

APA, Harvard, Vancouver, ISO, and other styles

18

卡伯特. "Studies on the Isolation, Identification and Applications of Low-Degree-Polymerization Algal Saccharides and Mechanism of Agaro-Polysaccharide Degradations." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/58585272611215701472.

Full text

Abstract:

博士 國立臺灣海洋大學 食品科學系 98 Ocean natural resources give us huge capabilities to utilize them for our healthier and better life. From the ocean we gain compounds with beneficial activity, and also additional instruments for their improvement. In this study saccharides from marine algae were examined as potential antiviral agents. For enhancement of their activity, the extracted algae-polysaccharides were digested to low-degree-polymerization (low-DP) saccharides; these are better available by life form. Tools for the polysaccharide digestions were enzymes, from marine bacteria. The best conditions for enzyme synthesis by one of the bacteria using in this study, Pseudomonas vesiculiaris MA103, were also studied. However, at the beginning, methods, basing on commercial standards, for optimal utilization of marine resources were established. Neoagaro-oligosaccharides (NAOS) or agaro-oligosaccharides (AOS) crude product mixtures from agarose were prepared by two high-performance liquid chromatography (HPLC) systems: size-exclusion chromatography (SEC) or NH2-column chromatography (NH2-HPLC) and monitored by an evaporative light-scattering detector (ELSD). Both HPLC systems clearly resolved individual saccharide products. However, SEC column enable the production of the saccharide products in milligram scale, while NH2-HPLC column allowed preparation of the products only in microgram scale. For the precise measurement of agarase hydrolysis activity a novel method, also utilizing SEC coupled with ELSD, was developed. The SEC-ELSD method was then compared with reducing sugar content methods, using routinely for assessment of the agarase activity. Results confirmed the high precision of SEC-ELSD method, whereas, RSC methods showed the agarase activity was underestimated when small amount of enzyme was used, and high amount of enzyme resulting in overestimation of agarase activity. Subsequently, low-DP sulfated saccharides from two algae, Gracilaria sp. and Monostroma nitidum were obtained by their polysaccharides (PS) digestion using MA103-agarases from P. vesiculiaris MA103 and MAEF108-agarases from Aeromonas salmonicida MAEF108. The production of the low-DP sulfated saccharides as well as activity of the agarases was performed as in preceding sections. The sulfated saccharides from algae with DP 6, 24 and 30 were inspected by 1H NMR spectroscopy and ESIMS spectrometry confirming structure, molecular mass, and purity. This part of study showed the methods established on commercial available standards (agarose and β-agarase) were successfully applied for preparation of low-DP sulfated saccharides from algal PS by digestions of agarases with defined activity. Then, the low-DP sulfated saccharides were tested for anti-Japanese encephalitis virus (anti-JEV) activity. Their activities were compared with undigested algal-PS. During in vitro studies performed by MTT assay, low-DP sulfated saccharides from both algae have slightly lower antiviral activities than their undigested-PS. However, the ELISA experiment results showed the low-DP sulfated saccharides bind to the JEV envelope protein at least strongly as undigested-PS. Results also showed, the low-DP sulfated saccharides have a distinctly higher positive effect on survivability in JEV infected C3H/HeN mice in comparison to undigested-PS (65-100% vs. 0-33% higher than control). The in vivo antiviral activity seems to be connected with better absorption of low-DP sulfated saccharides than undigested-PS, what was proved by measurement of sugar content in mice blood plasma. Our results point out that the low-DP sulfated saccharides are promising candidates for further development as antiviral agents. P. vesiculiaris MA103 was utilized for synthesis of MA103-agarases, when cultivating in medium (modified marine broth; MMB) with different carbon sources. Galactose, NAOS with DP from 4 to 20, agarose and agar were utilized as the carbon sources. Bacteria culturing in media with Gal-N8 at 90 sec mainly synthesized enzymes with MW 85-145 kDa, whereas these cultivating in media with N16-20, agarose and agar, initially produced enzymes with MW 25 and 29 kDa, then enzymes with MW 45 and 85 kDa. Interestingly, MA103-agarases from bacteria cultivating in various MMBs with different carbon sources had similar cleavage ability. Finally, all of them digested agarose to significant amount of N4, as well as smaller portion of N6, N2 and monomers. This study showed that the carbon source in media might have influence on synthesis of agarases by P. vesiculiaris MA103; however any distinct difference of their cleavage abilities on agarose were observed.

APA, Harvard, Vancouver, ISO, and other styles

19

HUANG, CI RUEI, and 黃啟睿. "Isolation and characterization of bacteria capable of biotransforming 5-hydroxymethylfurfural (5-HMF) to 2,5-furan dicarboxylic acid (FDCA) using algal acid hydrolysate." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/93787595333172570430.

Full text

Abstract:

碩士 國立雲林科技大學 環境與安全衛生工程系 103 The awakening to the fossil fuel limitation and sustainable development forces human to explore renewable and environmental friendly energy. Bioethanol is one potential candidate because it can be produced using pretreated lignocellulosic biomass, the most abundantly available raw material on the EarthIn recent years, algal biomass is considered as the idealraw material to produce renewable energy because of itshigh cellulosecontent and fast growth rate. Moreover, algae are well-known carbon dioxide capturer. Algae can be incubated in freshwater or seawater so thatthe land demand is minor. Taiwan is a small island country but surrounded by abundant algal resources. Using algal biomass for renewable energy production in Taiwan may be an ideal way to approach sustainable future. Thermal acid hydrolysis is extensively used to pretreat algal biomass because of economic and efficient consideration. However, the main drawback of thermal acid hydrolysis is to produce inhibitor compounds such as acetic acid, furfural and 5-hydroxymethyl furfural (5-HMF) during hydrolysis. These inhibitor compounds will influence downstream bioethanol fermentation. For better bioethanol yield, inhibitor compounds removal is an important issue. In 2004, US Department of Energy suggests top 14 biomass platform molecules for the sustainable future.. Among these compounds, 2,5-furan-dicarboxylic acid (FDCA) can be produced by 5-HMFbio-transformation. Basing on the connection between 5-HMF removal in the algal acid hydrolysate and FDCA production, microbes capable of biotransforming 5-HMF into FDCA could be beneficial to high bioethanol yield and potential molecule production. In this study, we collected algaChaetomorpha linumfrom waste fishing field as the raw material for thermal acid hydrolysis.To find out the best hydrolysis condition to obtain high reducing sugar concentration and hydrolysis efficiency, various parameters (acid sorts, algal concentrations, acid concentrationsand hydrolysis time) were investigated. In addition, potential microbes transforming 5-HMF into FDCA were enriched and isolated from an activated sludge tank of food factory and campus soil.Their abilities of 5-HMF biotransformation and FDCA production were investigated under various initial pHs, temperatures and 5-HMF concentrations. The isolates were also used to biotransform 5-HMF into FDCA in the algal acid hydrolysate. Optimum thermal acid hydrolysis condition was to apply0.5 M HCl to treat 3% algae at 121℃ for 15 minutes. The highest reducing sugar concentration and hydrolysis efficiencywere 6.32 g/L and 50%, respectively. There were 14 strains isolated from the activated sludge of soy sauce wastewater treatment system and the campussoil. Among these isolates, strain G-2 and H-2, the most potential two strains, were identified as Methylobacterium radiotolerans and Burkholderia cepacia, respectively, by 16S rDNA sequences.Strain MethylobacteriumradiotoleransG-2 could completely transform 1000 mg/L 5-HMF into FDCA at initial pH of 7 at 26C and maximum FDCA concentration was 513.9 mg/L. Strain Burkholderia cepacia H-2 transformed 2000 mg/L 5-HMF into FDCA at initial pH of 7 at 28C and 1276 mg/L FDCA was received.For 5-HMF biotransformation in the algal acid hydrolysate, 2-fold dilution was suitable for strain MethylobacteriumradiotoleransG-2, and 459.7 mg/L FDCA was obtained. Reducing sugar consumption was less than 16%. Strain Burkholderia cepacia H-2 was suitable to treat the algal hydrolysate without dilution, and 989.5 mg/L FDCA was received, but reducing sugar consumption was high, 43%.

APA, Harvard, Vancouver, ISO, and other styles

20

Shan, Shoau Yi, and 邵宜暄. "Multi-Energy Oxygen Ion Implantation Isolation for AlGaN/GaN HEMTs." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/55388355108130400693.

Full text

Abstract:

碩士 國立交通大學 材料科學與工程系所 92 GaN-based electron devices have received much attention due to their ability to operate at high power level and high temperature environment .Physical characters of AlGaN/GaN HEMTs like large energy bandgap, high electric breakdown field(5*106V/cm), high current density and good thermal stability make AlGaN/GaN HEMTs suitable for high power and high temperature applications. The contemporary isolation method is by using dry etch to define the device active region. But it’s difficult to dry etch GaN with a sloped side instead of a vertical cliff, which limits the etched depth since the connection metal lines may disconnect at deep vertical etched mesa sides. Moreover, in Ga-face polarization AlGaN/GaN structure, electrons which come from 2DEG may flow through the contact of gate metal line and accumulate at the surface region near the gate. This phenomenon may result in high gate leakage current and reduces G-D breakdown voltage. If the HEMT structure is the Ga-face polarization structure, electrons which accumulate at the surface may produce the current slump behavior that is often seen in the Id-Vd curve. Ion implantation, however, is a planar process which can avoid the problems mentioned above. Moreover, we discovered in our experiment that with proper implant energy and ion dosage, ion implantation is a better isolation process than mesa dry etch. The saturation current Idss is also improved. In our experiment, oxygen ions with different energies were multi-implanted into the AlGaN/GaN HEMT structure wafers. The energies used were 180kev + 90kev +75kev +35kev in sequence with the same 5*1014cm-2 dosages for each energy. First, Ti/Al/Ni/Au ohmic contact pads with different distances were used for implantation masks and then the leakage currents between the pads were measured to estimate isolation quality. Post heat treatments including RTA and tube annealing were then applied to test thermal stabilities. The leakage current between ohmic contact pads reached minimum value after 300℃ 1hr post-annealing. It is because hopping conduction was suppressed after defect clustering. And the leakage current arose at higher post-annealing temperatures with the formation of polycrystalline GaN at the implantation damaged region. We took XTEM pictures for un-implanted, as-implanted, 300℃ 1 hour post-annealed and 850℃ 1 hour post-annealed samples. The pictures of 300℃ post-annealed sample showed defect clustering compared to as-implanted sample. Therefore, hopping conduction was reduced and isolation quality was improved. Layer-by-layer transition from crystalline GaN to amorphous GaN beginning at the surface was also observed in the 300℃ post-annealed sample. For pictures of 850℃ 1 hour post-annealed sample we found that polycrystallization from amorphous GaN occurred. As a result, leakage current would flow through grain boundary and degraded isolation quality. AFM measurements showed that surface roughness didn’t change after implantation and post-annealing. After the leakage current measurement and material analysis, we applied this process to the HEMT fabrication. The fabrication process used S1818 photoresist as the implantation mask and we had achieved a planar device with high saturation current of 668mA/mm, maximum current of 833mA/mm, off-state breakdown voltage of 87V for 4.5um G-D spacing and peak transconductance of 288mS/mm. The current slump behavior was also suppressed compared with the AlGaN/GaN HEMTs using ICP mesa dry etch for isolation. Overall, this study shows that the AlGaN/GaN HEMTs device was improved by using multi-energy oxygen ion implantation isolation process compared with the device formed by conventional dry etch mesa isolation.

APA, Harvard, Vancouver, ISO, and other styles

21

陳筌鴻. "Isolation and characterization of oil-rich algae from fish pond." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/60559914445216423670.

Full text

Abstract:

碩士 國立嘉義大學 生物農業科技學系碩士班 98 Since the industrial revolution , long-term use of fossil oil as a fuel source rapidly depletes oil production and supply can not be sustained for long-term needs. Long-term use of fossil fuels also causes environmental pollution and because of CO2 and other greenhouse gases, which caused the Earth's temperature to rise. In addition,the rise of China and India demands significant increases in energy consumption. Therefore, without a significant impact on the current way of life and environmental protection, alternative sources of energy (Alternative energy) must be adopted .Bioenergy would be a good solution. Bioenergy comes from the convertion of organic material into energy, which has the advantages of different forms of environmental protection and sustainability (Renewable). From an efficiency point of view, biodiesel is advanfageous over bioethanol. Therefore, biodiesel is considered a good energy source. Use of microalgae for biodiesel production has the advantage that algae can grow rapidly with low water consumption in comparison to culture of food crops. For all these reasons, it is clear that use of microalgae for biodiesel production in the future can not only absorb carbon dioxide, but also reduce CO2 emission . Algae have a fast rate of growth in comparison to other energy crops. In this study, two algae species, A and B, were isolated from fish pond water and molecular biological analysis revealed that A was identified as a Chlorella sp., but B was not identifiable by this approach. The oil content of algae A (Chlorella sp.) can be as high as 55% while the oil content of algae B can be as high as 70% . Furthermore, by using Agrobacterium for genetic transformation in algae A for expression of foreign proteins, it can increase the commercial value of the microalgae.

APA, Harvard, Vancouver, ISO, and other styles

22

Chang, Ting-Fu, and 張庭輔. "The characteristic of AlGaN/GaN HEMT with different isolation and epitaxial layers." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/22679672024643300365.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

VORÁČOVÁ, Kateřina. "Isolation of intact plastids of the secondary alga \kur{Chromera velia} and treatment of the alga with rifampicin." Master's thesis, 2011. http://www.nusl.cz/ntk/nusl-54440.

Full text

Abstract:

Photosynthetic organism Chromera velia was discovered recently. Thanks to the fact that it is harmless algae but close relative to apicomplexan parasites it could be used as a helpful-tool for basic research. Apicoplast serves as a target of some antimalarial agents, so my first task was to isolate pure fraction of plastid organelle. And next to apply antibiotic rifampicin at the same doses that are working in Plasmodium falciparum to see whether it would be possible to use C. velia as a model organism in first screening of new antimarial drugs.

APA, Harvard, Vancouver, ISO, and other styles

24

Knuckey, RMP. "Isolation of Australian microalgae and preparation of microalgal concentrates for use as aquaculture feeds." Thesis, 1998. https://eprints.utas.edu.au/20457/7/whole_KnuckeyRichardMichaelPhillip1999.pdf.

Full text

Abstract:

In this study, two types of microalgal feed were examined; 1) algal concentrates and 2) new Australian microalgae. Algal concentrates were examined because for aquaculturists, they could provide an off-the-shelf alternative to maintaining live algal cultures. Australian microalgae were examined to identify new feed species and to determine specific dietary requirements of local juvenile Pacific oysters (Crassostrea gigas). Ten diatoms, microalgae widely cultivated as feed for aquaculture species, were isolated and purified from local waters, Tasmania, Australia. Proximate analysis of logarithmic and stationary phase cultures showed major differences between species and in the effect of stationary phase on composition. Four species (Attheya septentrionalis, Entomoneis cf. punctulata, Extubocellulus spinifera and Thalassiosira oceanica) were evaluated as feed for juvenile Pacific oysters. Fed as the major component in a ternary algal diet, two algae (Attheya septentrionalis and Entomoneis cf. punctulata) supported over 80% of the growth of the T. pseudonana control. Centrifugation of eleven microalgae from a range of classes showed it to be an efficient (>80 % recovery) way to concentrate microalgae. Small chlorophytes survived the high shear forces best but, are documented poor algal diets for oysters. Of the diatoms Chaetoceros calcitrans and Thalassiosira pseudonana were least damaged. Juvenile oyster feeding trials showed that T. pseudonana pastes were capable of sustaining limited growth. However, nutritional deficiencies in the pastes were reflected in falling weekly growth rates, by the third week, oysters grew only marginally or lost organic weight. An alternative, low shear concentration process was developed based on chemical induced flocculation. Initial coagulation of algae was induced using Fe +3 or by increasing pH. Flocculated concentrates of T pseudonana were fed to juvenile Pacific oysters and compared to live T. pseudonana and centrifuged algal pastes. The pH flocculated algal diet was superior to all other test diets and lost nutritional value more slowly than centrifuged algal diets. In the discussion the nutritional composition of algal diets is related to the composition and nutritional requirements of the juvenile oysters. It is argued that the dietary protein content of live algal diets, not limited in essential nutrients, is the most significant factor in determining a nutritionally superior diet. The nutritional value of algal concentrates is discussed and flocculation is concluded to be a superior method to produce concentrates. It is shown that flocculation is applicable for concentrating many algal species and argued that it is a cost-effective process with commercial applications.

APA, Harvard, Vancouver, ISO, and other styles

25

AlOtaibi, Bandar. "Fin and Island Isolation of AlGaN/GaN HFETs and Temperature-dependent Modeling of Drain Current Characteristics of AlGaN/GaN HFETs." Thesis, 2011. http://spectrum.library.concordia.ca/7646/1/AlOtaibi_MSc_F2011.pdf.

Full text

Abstract:

Over the past two decades AlGaN/GaN Heterostructure Field Effect Transistors (HFETs) have been the target of many studies on their suitability for high-power and high-temperature applications. Due to the sizable inherent polarization effects, present in these heterostructure-based devices, the built-in sheet charge density at the AlGaN/GaN heterointerface is remarkably high, which makes these devices fall into the category of the depletion-mode field effect transistors. Despite the suitability of this wide-bandgap material system for switching power applications, the depletion-mode character of these HFETs has been acting as an obstacle against the adoption of AlGaN/GaN HFETs to these applications. As a result, a vibrant research on the development of techniques capable of reliably changing the depletion-mode character of AlGaN/GaN HFETs into an enhancement-mode character is currently being pursued by many investigators. Towards this end, the proposed approach of this thesis has been based on modifying the piezoelectric component of the polarization sheet charge density through studying its correlation with the size of the isolation mesa. The impact of the size of the isolation-mesa on the sweeping- and pulsed-mode drain current-voltage characteristics of AlGaN/GaN HFETs has been studied. Investigations reveal that while by implementing AlGaN/GaN HFETs on array of islands or mesas of smaller dimensions, rather than one continuous-mesa, same values for the maximum drain current level can be maintained, pinch-off voltage can be made less negative. Also, it is shown that the maximum gate transconductance is improved by island-type isolation. In addition, it is shown that the proportionally larger surface area available for power dissipation in fin- and island-isolated HFETs can reduce the impact of self-heating on AlGaN/GaN HFETs. Modeling the drain current of AlGaN/GaN HFETs at high-temperature ambient was also another objective of this thesis. A Monte Carlo-based temperature-dependent mobility model, with incorporation of steady-state velocity overshoot, is employed in modeling the drain current-voltage characteristics of AlGaN/GaN HFETs at 300, 400, and 500K. One of the major merits of this model is that it employs a very small set of fitting parameters. The model takes into account the temperature-dependence of the electron transport through the gated-channel of an AlGaN/GaN HFET and also its access regions. This model is validated with regards to the experimentally measured drain current characteristics. Results confirm that the temperature dependency of the drift electron velocity is the cause of the degradation of drain current at elevated temperatures.

APA, Harvard, Vancouver, ISO, and other styles

26

Wu, Shih-Yang, and 吳士暘. "Isolation and preliminary characterization of a novel algae-lysis compound from Bacillus thuringiensis." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/82965386922711240502.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

XU, NONG-FENG, and 徐農豐. "The preparation, isolation and regeneration of protoplast from four species of brown algae." Thesis, 1992. http://ndltd.ncl.edu.tw/handle/06322180220904460096.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

"Isolation, Purification and Characterization of Photosynthetic Membrane Proteins from Galdieria sulphuraria and Chlamydomonas reinhardtii." Doctoral diss., 2010. http://hdl.handle.net/2286/R.I.8662.

Full text

Abstract:

abstract: In oxygenic photosynthesis, Photosystem I (PSI) and Photosystem II (PSII) are two transmembrane protein complexes that catalyze the main step of energy conversion; the light induced charge separation that drives an electron transfer reaction across the thylakoid membrane. Current knowledge of the structure of PSI and PSII is based on three structures: PSI and PSII from the thermophilic cyanobacterium Thermosynechococcus elonagatus and the PSI/light harvesting complex I (PSI-LHCI) of the plant, Pisum sativum. To improve the knowledge of these important membrane protein complexes from a wider spectrum of photosynthetic organisms, photosynthetic apparatus of the thermo-acidophilic red alga, Galdieria sulphuraria and the green alga, Chlamydomonas reinhardtii were studied. Galdieria sulphuraria grows in extreme habitats such as hot sulfur springs with pH values from 0 to 4 and temperatures up to 56°C. In this study, both membrane protein complexes, PSI and PSII were isolated from this organism and characterized. Ultra-fast fluorescence spectroscopy and electron microscopy studies of PSI-LHCI supercomplexes illustrate how this organism has adapted to low light environmental conditions by tightly coupling PSI and LHC, which have not been observed in any organism so far. This result highlights the importance of structure-function relationships in different ecosystems. Galdieria sulphuraria PSII was used as a model protein to show the amenability of integral membrane proteins to top-down mass spectrometry. G.sulphuraria PSII has been characterized with unprecedented detail with identification of post translational modification of all the PSII subunits. This study is a technology advancement paving the way for the usage of top-down mass spectrometry for characterization of other large integral membrane proteins. The green alga, Chlamydomonas reinhardtii is widely used as a model for eukaryotic photosynthesis and results from this organism can be extrapolated to other eukaryotes, especially agricultural crops. Structural and functional studies on the PSI-LHCI complex of C.reinhardtii grown under high salt conditions were studied using ultra-fast fluorescence spectroscopy, circular dichroism and MALDI-TOF. Results revealed that pigment-pigment interactions in light harvesting complexes are disrupted and the acceptor side (ferredoxin docking side) is damaged under high salt conditions. Dissertation/Thesis Ph.D. Biochemistry 2010

APA, Harvard, Vancouver, ISO, and other styles

29

"Isolation of actin gene fragments from Chlorella vulgaris and the construction of transgenic cassettes for the production of bacillus: toxin in Chlorella vulgaris." Chinese University of Hong Kong, 1995. http://library.cuhk.edu.hk/record=b5895593.

Full text

Abstract:

by Chow Fung-cheung, Judy. Thesis (M.Phil.)--Chinese University of Hong Kong, 1995. Includes bibliographical references (leaves 106-117). ACKNOWLEDGMENT --- p.i ABSTRACT --- p.ii TABLE OF CONTENTS --- p.iv LIST OF ABBREVIATIONS --- p.ix LIST OF FIGURES AND TABLES --- p.xii Chapter SECTION I- --- ISOLATION OF ACTIN GENE FRAGMENTS FROM CHLORELLA VULGARIS Chapter CHAPTER 1: --- INTRODUCTION Chapter 1.1 --- Functions of Actin --- p.1 Chapter 1.1.1 --- Functions of Actin in Animals --- p.1 Chapter 1.1.2 --- Functions of Actin in Plants --- p.2 Chapter 1.1.2.1 --- In Lower Plants --- p.2 Chapter 1.1.2.2 --- In Higher Plants --- p.2 Chapter 1.2 --- Molecular Studies of Actin Gene Families in Plants --- p.4 Chapter 1.2.1 --- Multigene Family --- p.4 Chapter 1.2.2 --- Homologies Across Kingdom --- p.4 Chapter 1.2.3 --- Homologies Within Kingdom --- p.5 Chapter 1.2.4 --- Position of Intron --- p.5 Chapter 1.2.5 --- Differential Expression of Actin Genes --- p.7 Chapter 1.3 --- Objectives of Present Studies --- p.7 Chapter CHAPTER 2: --- GENERAL TECHNIQUES Chapter 2.1 --- Growth of Algal Strain --- p.9 Chapter 2.2 --- Growth of Bacterial Strains --- p.10 Chapter 2.3 --- Agarose Gel Electrophoresis --- p.10 Chapter 2.4 --- Restriction Enzyme Digestion --- p.10 Chapter 2.5 --- Recovery of DNA Fragments from Agarose Gel --- p.11 Chapter 2.5.1 --- Glass Powder Elution of DNA --- p.11 Chapter 2.5.2 --- Sephaglas´ёØ BandPrep Kit --- p.11 Chapter 2.6 --- Large Scale Preparation of Plasmid by Using Magic´ёØ Maxipreps DNA Purification System --- p.12 Chapter 2.7 --- Ligation --- p.13 Chapter 2.8 --- Preparation of Competent Cells --- p.13 Chapter 2.9 --- Transformation of Competent Cells --- p.14 Chapter 2.10 --- Screening of Recombinant Plasmids --- p.14 Chapter 2.11 --- Spun Column Techniques --- p.15 Chapter CHAPTER 3: --- PCR-CLONING OF ACTIN GENE FRAGMENTS FROM CHLORELLA VULGARIS Chapter 3.1 --- Introduction --- p.16 Chapter 3.2 --- Materials and Methods --- p.16 Chapter 3.2.1 --- Preparation of Genomic DNA from C. vulgaris --- p.16 Chapter 3.2.2 --- Amplification of Actin Genomic Fragments by PCR --- p.17 Chapter 3.2.3 --- Cloning of PCR Products --- p.17 Chapter 3.2.4 --- Southern Blotting --- p.18 Chapter 3.2.5 --- Radiolabeling of DNA Probe --- p.19 Chapter 3.2.6 --- Prehybridization and Hybridization --- p.19 Chapter 3.2.7 --- Sequencing Strategies --- p.20 Chapter 3.2.7.1 --- Isolation of Template DNA --- p.20 Chapter 3.2.7.2 --- Template Denaturation and Primer Annealing --- p.21 Chapter 3.2.7.3 --- Labeling and Termination Reaction --- p.21 Chapter 3.2.7.4 --- DNA Sequencing Electrophoresis --- p.21 Chapter 3.3 --- Results and Discussion --- p.22 Chapter CHAPTER 4: --- CLONING OF ACTIN COMPLEMENTARY DNA FRAGMENT FROM CHLORELLA VULGARIS Chapter 4.1 --- Introduction --- p.31 Chapter 4.2 --- Materials and Methods --- p.31 Chapter 4.2.1 --- Preparation of RNA --- p.31 Chapter 4.2.2 --- RT-PCR --- p.32 Chapter 4.2.3 --- Southern Blotting and Hybridization --- p.32 Chapter 4.2.4 --- Radiolabeling of DNA Probe --- p.32 Chapter 4.2.5 --- Cloning of RT-PCR Product --- p.33 Chapter 4.2.6 --- DNA Sequencing --- p.33 Chapter 4.2.7 --- Sequence Analysis --- p.33 Chapter 4.3 --- Results and Discussion --- p.34 Chapter CHAPTER 5: --- SEQUENCE COMPARISON OF ACTIN GENES Chapter 5.1 --- Introduction --- p.44 Chapter 5.2 --- Materials and Methods --- p.44 Chapter 5.3 --- Results and Discussion --- p.44 Chapter 5.3.1 --- Nucleotide Sequence Analysis --- p.44 Chapter 5.3.2 --- Analysis of the Predicted Amino Acid Sequence --- p.49 Chapter 5.3.3 --- Codon Usage --- p.49 Chapter 5.3.4 --- Intron-Exon Structure in Plant Actin Genes --- p.51 Chapter 5.3.5 --- General Discussion --- p.53 Chapter CHAPTER 6: --- ISOLATION OF FURTHER UPSTREAM SEQUENCE FOR ACTIN GENE (CAc18G) FROM CHLORELLA VULGARIS Chapter 6.1 --- Introduction --- p.54 Chapter 6.2 --- Materials and Methods --- p.54 Chapter 6.2.1 --- Genomic Southern Analysis --- p.54 Chapter 6.2.2 --- Preparation of Actin-Enriched DNA Fraction --- p.55 Chapter 6.2.3 --- Ligation of Actin-Enriched Fragments with Specific DNA Cassette --- p.55 Chapter 6.2.4 --- Amplification of Upstream Sequence by Nested PCR --- p.55 Chapter 6.2.5 --- DNA Sequencing --- p.56 Chapter 6.3 --- Results and Discussion --- p.57 Chapter SECTION II - --- CONSTRUCTION OF TRANSGENIC CASSETTES FOR THE PRODUCTION OF BACILLUS TOXIN IN CHLORELLA VULGARIS Chapter CHAPTER 1： --- INTRODUCTION Chapter 1.1 --- Characteristics of Algae --- p.64 Chapter 1.2 --- Biotechnology Potential of Algae --- p.66 Chapter 1.3 --- Transgenic Algae --- p.68 Chapter 1.3.1 --- Genes of Selection for Transformant --- p.70 Chapter 1.3.1.1 --- Homologous Genes --- p.70 Chapter 1.3.1.2 --- Heterologous Genes --- p.70 Chapter 1.3.2 --- Transformation Technologies Used in Algae --- p.71 Chapter 1.3.3 --- Expression of Transgenes in Algae --- p.73 Chapter 1.4 --- Bacillus Toxin --- p.73 Chapter 1.4.1 --- Bacillus thuringiensis --- p.73 Chapter 1.4.2 --- Classification of Bacillus Toxin Genes (Cry Genes) --- p.74 Chapter 1.4.2.1 --- Type I (CtyI Genes) --- p.74 Chapter 1.4.2.2 --- Type II (CryII Genes) --- p.75 Chapter 1.4.2.3 --- Type III (CryIII Genes) --- p.76 Chapter 1.4.2.4 --- Type IV (CryIV Genes) --- p.76 Chapter 1.4.3 --- Mode of Action of Insecticidal Effects --- p.77 Chapter 1.5 --- Insect-Resistance Transgenic Plants --- p.78 Chapter 1.5.1 --- Transgenic Plants Expressing Crystal Protein Gene --- p.79 Chapter 1.5.2 --- Problems Encountered --- p.80 Chapter 1.6 --- Aims of Present Studies --- p.80 Chapter CHAPTER 2: --- CONSTRUCTION OF TRANSGENIC CASSETTES Chapter 2.1 --- Introduction --- p.82 Chapter 2.2 --- Materials and Methods --- p.82 Chapter 2.2.1 --- Preparation of Plasmids Involved in the Construction of Master Cassette --- p.82 Chapter 2.2.2 --- Construction of Master Cassette --- p.83 Chapter 2.2.3 --- Multiple Cloning Site (MCS) of Master Cassette --- p.83 Chapter 2.2.4 --- Preparation of Plating Cells --- p.85 Chapter 2.2.5 --- Titering --- p.85 Chapter 2.2.6 --- Preparation of Plate Lysate --- p.86 Chapter 2.2.7 --- Amplification of Coding Region of CryIVC Gene --- p.86 Chapter 2.2.8 --- Cloning of PCR Products --- p.87 Chapter 2.2.9 --- Construction of Transgenic Cassette --- p.87 Chapter 2.2.10 --- Confirmation of the Junction Sites --- p.89 Chapter 2.2.11 --- Testing for the Sensitivity of Algae Towards Kanamycin --- p.90 Chapter 2.3 --- Results and Discussion --- p.91 Chapter CHAPTER 3: --- TRANSFORMATION OF ALGAE BY ELECTROPORATION Chapter 3.1 --- Introduction --- p.97 Chapter 3.2 --- Materials and Methods --- p.97 Chapter 3.2.1 --- Harvesting of Algae --- p.97 Chapter 3.2.2 --- Electroporation at Different Field Strength --- p.98 Chapter 3.2.3 --- Plating Culture of Algal Cells --- p.98 Chapter 3.2.4 --- Preparation of Plasmids for Electrop oration --- p.98 Chapter 3.2.5 --- Transformation of Algae --- p.100 Chapter 3.2.6 --- Study on the Uptake of DNA after Electrop oration --- p.100 Chapter 3.2.6.1 --- Genomic DNA Preparation --- p.100 Chapter 3.2.6.2 --- Analysis of DNA Uptake --- p.101 Chapter 3.3 --- Results and Discussion --- p.101 REFERENCES --- p.106 APPENDIX --- p.118

APA, Harvard, Vancouver, ISO, and other styles

30

Petrie, James. "Isolation and characterisation of polyunsaturated fatty acid biosynthesis genes from Pavlova salina." Phd thesis, 2006. http://hdl.handle.net/1885/149603.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Lee, Chen-I., and 李貞儀. "Affinity isolation and mass spectrometric analysis of distorted DNA-binding proteins in unicellular alga Chlorella pyrenoidosa." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/14047891889689134335.

Full text

Abstract:

碩士 國立臺灣海洋大學 生物科技研究所 92 ABSTRACT Distorted DNA helical structures induced by covalent chemical adducts or mismatched nucleotides are removed by specific DNA repair pathways and these repair systems are initiated by the binding of damage-recognition proteins to DNA lesions. Distorted DNA-binding proteins in lower plants are studied in this thesis by electrophoretic mobility shift assay(EMSA), affinity adsorption, 2-D gel electrophoresis and mass spectrometric analysis using the unicellular alga Chlorella pyrenoidosa as a model system. A duplex oligonucleotide carrying either a cisplatin-induced intrastrand G-G crosslinking or a G-T mispair was found to attract some algal binding proteins as shown by EMSA. No polypeptides binding preferentially to a G-T mismatch probe immobilized on magnetic particles were found by SDS-PAGE.A 13-kDa G-T binding factor,however,was detected by fluorescence staining after 2-D gel electrophoresis and this polypeptide had an acidic pI value about 5.0. No proteins contained in the Mascot database could be matched significantly to this mismatch binding protein based on peptide mass fingerprint (PMF), although some sequence homology to ORF 41C of Chlorella vulgaris was observed. Thus, this mismatch binding protein was thought to be produced specifically in Chlorella pyrenoidosa.The 13-kDa polypeptide was shown to bind 2.5-fold stronger to heteroduplex than to homoduplex DNA according to quantitative image analysis. A 65 to 70-kDa polypeptide having molecular mass very similar to the 70-kDa factor involved in nucleotide excision repair of C. pyrenoidosa (Hsu et al, 2000) was preferentially captured by immobilized cisplatin-damaged DNA in affinity adsorption. The 70-kDa algal polypeptide was later shown to comprise multiple damage-recognition factors having very close molecular weights and pIs after a series of 2-D electrophoresis using IPG strips containing macro- to micro-range pH gradients from 3-10, 4-7 to 4.7-5.9. Five polypeptides with molecular weights between 52.09 to 57.55 kDa and pIs between 5.07 to 5.23 were detected after the micro-range pI separation. Hence, these five polypeptides each with a 1.2 to 1.5 stronger affinity for distorted helical structures might accumulate as a single spot near 70 kDa when separated by a macro-range pI gradient. Mass spectrometric analysis of the cisplatin-damaged-DNA binding proteins are underway.

APA, Harvard, Vancouver, ISO, and other styles

32

Saputri, Elfida, and 艾菲達. "Isolation and Characterization of Proteins from Green Algae (Ulva lactuca) and Prediction of Bioactive Peptides Using Bioinformatics Tools." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/12372871222200519038.

Full text

Abstract:

碩士 國立臺灣海洋大學 食品科學系 104 Based on pigmentation, macroalgae can be classified as brown algae (Phaeophyceae), red algae (Rhodopyceae) and green algae (Chloropyceae). Recently, macroalgae are regarded as great potential sources of plant proteins with increasing need. In this study, green algae Ulva lactuca was selected due to its protein content (3.45–29.00 %, dry basis), which is moderately high in green algae group. The objectives were to evaluate the protein extraction methods in Ulva lactuca, to identify molecular characteristic using polyacrylamide gel electrophoresis (SDS–PAGE) and proteomics techniques, to predict bioactive peptides and the potential biological activities in using bioinformatics tools (UniProt/KB and BIOPEP database). In order to isolate the protein fraction from green algae, two extraction methods were performed: aqueous and alkaline (0.1 M NaOH) extraction, and precipitate using 10% TCA/acetone. Alkaline extraction had the highest yield (17.29 ± 4.38%) than aqueous extraction (14.77 ± 6.86%). With SDS-PAGE characterization, molecular weight (MW) of protein subunits were identified as follows: 34.6 kDa (A1), 23.7 kDa (A2), 10 kDa (A3) and 13.4 kDa (B1). The protein bands A1, A2 and B1 were comparable with reported Ulva sp protein sequence; (A1) elongation factor Tu (MW: 32.7 kDa), (A2) ferritin (MW: 22.2 kDa) and (B1) cytochrome b6/f complex subunit IV (MW: 12.8 kDa) protein. The subsequent in silico analysis was carried out using BIOPEP database to predict bioactive peptides with reported biological activities. The predictive results showed that the Ulva lactuca proteins have the highest occurrence frequency of potential bioactivities in dipeptidyl peptidase (DPP)-IV inhibitors, followed by angiotensin converting enzyme (ACE) inhibitors, antioxidative, antiamnestic, antithrombotic, and a small amount of antibacterial and neuropeptide. In silico hydrolysis using “BIOPEP” enzyme action tools” with 27 proteases revealed that hydrolysis with ficain (elongation factor Tu), papain (ferritin) and proteinase K (cytochrome b6/f complex subunit IV) released greater numbers of predicted bioactive peptides compared to others proteases.

APA, Harvard, Vancouver, ISO, and other styles

33

"Isolation and characterization of alginate from Hong Kong brown seaweed: an evaluation of the potential use of the extracted alginate as food ingredient." 2000. http://library.cuhk.edu.hk/record=b5895798.

Full text

Abstract:

by Li Yung Yung. Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. Includes bibliographical references (leaves 105-121). Abstracts in English and Chinese. ACKNOWLEDGEMENTS --- p.i ABSTRACT (ENGLISH VERSION) --- p.ii ABSTRACT (CHINESE VERSION) --- p.iv TABLE OF CONTENTS --- p.v LIST OF TABLES --- p.x LIST OF FIGURES --- p.xi LIST OF ABBREVIATIONS --- p.xiii Chapter CHAPTER ONE --- INTRODUCTION Chapter 1.1 --- Seaweed --- p.1 Chapter 1.1.1 --- General Introduction --- p.1 Chapter 1.1.2 --- Classification and Use of Seaweed --- p.1 Chapter 1.1.3 --- Phycocolloids --- p.2 Chapter 1.1.4 --- Hong Kong Seaweed --- p.3 Chapter 1.1.4.1 --- Sargassum Species --- p.3 Chapter 1.1.4.2 --- Padina Species --- p.5 Chapter 1.2 --- Source and Production of Alginate --- p.8 Chapter 1.2.1 --- Function of Alginate in Seaweed --- p.8 Chapter 1.2.2 --- Chemical Structure of Alginate --- p.8 Chapter 1.2.3 --- Alginate Production --- p.9 Chapter 1.2.4 --- Isolation of Alginate --- p.13 Chapter 1.2.5 --- Commercial Methods --- p.13 Chapter 1.3 --- Application of Alginate --- p.14 Chapter 1.3.1 --- Industrial Application --- p.14 Chapter 1.3.2 --- Pharmaceutical Application --- p.16 Chapter 1.3.3 --- Food Application --- p.17 Chapter 1.3.3.1 --- Uses of Alginate in Food --- p.17 Chapter 1.3.3.2 --- Safety --- p.19 Chapter 1.4 --- Structure and Function Relationship of Alginate --- p.19 Chapter 1.4.1 --- Physico-Chemical Properties --- p.21 Chapter 1.4.1.1 --- M/G ratio --- p.21 Chapter 1.4.1.2 --- Solution Properties --- p.21 Chapter 1.4.1.3 --- Viscosity --- p.23 Chapter 1.4.1.4 --- Molecular Weight --- p.27 Chapter 1.4.2 --- Functional Properties --- p.27 Chapter 1.4.2.1 --- Emulsion --- p.27 Chapter 1.4.2.2 --- Gel Properties --- p.27 Chapter 1.4.2.3 --- Mechanism of Gelation --- p.29 Chapter 1.4.2.4 --- Gel Strength and Syneresis --- p.30 Chapter 1.5 --- Physiological Effects --- p.32 Chapter 1.5.1 --- Dietary Fibre --- p.32 Chapter 1.5.2 --- Minerals --- p.32 Chapter 1.6 --- Significance of the Present Study --- p.33 Chapter CHAPTER TWO --- MATERIALS AND METHODS Chapter 2.1 --- Seaweed Collection --- p.36 Chapter 2.2 --- Sample Preparation --- p.36 Chapter 2.3 --- Alginate Extraction --- p.38 Chapter 2.3.1 --- Method A --- p.38 Chapter 2.3.2 --- Method B --- p.38 Chapter 2.3.3 --- Commercial Alginate --- p.39 Chapter 2.4 --- Chemical Composition of Alginate --- p.41 Chapter 2.4.1 --- Alginate Content --- p.41 Chapter 2.4.2 --- Moisture Content --- p.41 Chapter 2.4.3 --- Crude Protein Content --- p.41 Chapter 2.4.4 --- Ash Content --- p.42 Chapter 2.4.5 --- Monosaccharide Composition --- p.42 Chapter 2.4.5.1 --- Acid Deploymerisation --- p.42 Chapter 2.4.5.2 --- Neutral and Amino Sugar Derivatization --- p.42 Chapter 2.4.5.3 --- Determination of Neutral Sugars by Gas Chromatography --- p.43 Chapter 2.4.5.4 --- Uronic Acid Content --- p.44 Chapter 2.4.6 --- Uronic Acid Block Composition --- p.44 Chapter 2.4.6.1 --- "MG, MM and GG Block Determination" --- p.44 Chapter 2.4.6.2 --- M/G Ratio Determination --- p.45 Chapter 2.4.6.3 --- Phenol-Sulfuric Acid Method --- p.45 Chapter 2.5 --- Physico-Chemical Properties of Alginate --- p.46 Chapter 2.5.1 --- Viscosity --- p.46 Chapter 2.5.1.1 --- Ostwald Viscometer --- p.46 Chapter 2.5.1.2 --- Brookfield Viscometer --- p.47 Chapter 2.5.2 --- Molecular Weight --- p.47 Chapter 2.5.2.1 --- From Intrinsic Viscosity --- p.47 Chapter 2.5.2.2 --- Gel Permeation Chromatography-Laser Light Scattering (GPC-LLS) --- p.48 Chapter 2.6 --- Functional Properties of Alginate --- p.49 Chapter 2.6.1 --- Emulsifying Activity (EA) and Emulsion Stability (ES) --- p.49 Chapter 2.6.2 --- Gel Formation --- p.49 Chapter 2.6.3 --- Gel Strength and Syneresis --- p.50 Chapter 2.6.4 --- Application in Food ´ؤ Fruit Jelly --- p.52 Chapter 2.7 --- Data Analysis --- p.53 Chapter CHAPTER THREE --- RESULTS AND DISCUSSION Chapter 3.1 --- Proximate Composition of Selected Seaweed --- p.54 Chapter 3.1.1 --- Moisture Content --- p.54 Chapter 3.1.2 --- Ash Content --- p.56 Chapter 3.1.3 --- Crude Protein Content --- p.57 Chapter 3.1.4 --- Carbohydrate Content --- p.58 Chapter 3.2 --- Chemical Composition of Alginate Extracted from Two Different Methods --- p.58 Chapter 3.2.1 --- Percentage Yield --- p.59 Chapter 3.2.2 --- Alginate Content --- p.61 Chapter 3.2.3 --- Moisture Content --- p.62 Chapter 3.2.4 --- Ash Content --- p.62 Chapter 3.2.5 --- Residual Protein Content --- p.63 Chapter 3.2.6 --- Monosaccharide Composition of Alginate --- p.63 Chapter 3.2.7 --- M/G Ratio --- p.66 Chapter 3.2.8 --- Summary --- p.69 Chapter 3.3 --- Comparative Studies of Physico-Chemical Composition of Alginate from Sargassum and Padina Species --- p.71 Chapter 3.3.1 --- Block Composition and M/G Ratio --- p.71 Chapter 3.3.2 --- Viscosity --- p.75 Chapter 3.3.2.1 --- Intrinsic Viscosity ´ؤ Capillary Viscometer --- p.75 Chapter 3.3.2.2 --- Solution Viscosity - Brookfield Viscometer --- p.79 Chapter 3.3.2.2.1 --- Effect of Temperature --- p.79 Chapter 3.3.2.2.2 --- Effect of Concentration --- p.81 Chapter 3.3.2.2.3 --- Shear Thinning and Time Independent Effect --- p.82 Chapter 3.3.3 --- Molecular Weight --- p.88 Chapter 3.3.3.1 --- From Intrinsic Viscosity --- p.88 Chapter 3.3.3.2 --- Gel Permeation Chromatograph-Laser Light Scattering (GPC-LLS) --- p.90 Chapter 3.4 --- Comparative Studies of the Functional Properties of Extracted Alginate with Commercial Alginate --- p.93 Chapter 3.4.1 --- Emulsifying Activity (EA) and Emulsifying Stability (ES) --- p.93 Chapter 3.4.2 --- Gelling Properties --- p.95 Chapter 3.4.2.1 --- Effect of Calcium Concentrations --- p.95 Chapter 3.4.2.2 --- Gel Strength and Syneresis --- p.97 Chapter 3.4.3 --- Application in Food --- p.99 Chapter CHAPTER FOUR --- CONCLUSIONS --- p.103 REFERENCES --- p.105 RELATED PUBLICATION --- p.120

APA, Harvard, Vancouver, ISO, and other styles

34

Harnett, Julia Patricia. "Isolation and characterization of photosystem I and the fucoxanthin-chlorophyll a/c proteins of the chromophyte alga Heterosigma carterae." Thesis, 1998. http://hdl.handle.net/2429/8124.

Full text

Abstract:

The chromophyte algae are a large and diverse group of organisms. They are unique in that they possess four membranes surrounding the chloroplast, as well as chlorophyll c. Compared to higher plants relatively little is known regarding the photosynthetic proteins of the chromophytes. In particular, much less is known regarding the light-harvesting proteins (FCPs) and the photosystems with which they are associated. FCPs (fucoxanthin-chl ale proteins) are the light-harvesting proteins found in chromophytes and they are part of an extended light-harvesting protein family which includes the chl a/b proteins (CABs) of chlorophytes and rhodophytes, as well as the peridinin-chlorophyll- a/c proteins (PCPs) of dinoflagellates. In the chromophytes it is not known how the different FCPs are related to each other or where FCPs are located within the thylakoids, i.e. if there are any specific associations with either PSI or PSII. In order to understand a little more about these photosynthetic proteins in chromophytes, I have developed several methods, and modified others, to separate out photosynthetic proteins of the chromophyte Heterosigma carterae. Using sucrose density gradients and FPLC (perfusion chromatography) to separate out dodecyl-p-D-maltoside- or digitonin-solubilized thylakoids, I obtained different FCP fractions, as well as several different PSI fractions with associated FCPs. With each type of detergent solubilization a large fraction of FCPs were released. The FCP fraction of the digitonin sucrose gradient contained mostly the main FCP (19.5 kDa). This fraction was further purified and an antibody raised to the main FCP. Immunological analyses with the anti-FCP antibody and the anti-CPIa antibody (known to cross-react with several H. carterae FCPs) showed further evidence supporting a monophyletic origin of the light-harvesting proteins in the different photosynthetic eukaryotes. The FCP band from the DM-gradient contained several FCPs, some of which could be further purified through FPLC. Two minor FCPs were purified for N-terminal sequencing. However, only weak homology was found with any other photosynthetic proteins, none of these being light-harvesting proteins. There was one main PSI fraction found with each of the detergent solubilizations, as well as a few minor PSI complexes in the digitonin-solubilized thylakoids. These fractions were characterized by polypeptide analysis (SDS-PAGE and Western blotting), pigment analysis (absorbance measurements), activity measurements (chl a/P700), dimensions (electron microscopy), and extrinsic protein determination (salt washes). A sucrose gradient PSI sample was further purified by FPLC to see if any other PSI proteins could be removed. The general characteristics of chromophyte PSI, particularly the polypeptides, were quite similar to higher plant and cyanobacteria. There also appeared to be several FCPs, including the main FCP, associated with PSI. However, whether these FCPs were exclusive to PSI could not be determined at this time.

APA, Harvard, Vancouver, ISO, and other styles

35

Barreto, Michael. "Antimicrobial activity of macroalgae from Kwazulu-Natal, South Africa, and the isolation of a bioactive compound from Osmundaria serrata (Rhodophyta)." Thesis, 2003. http://hdl.handle.net/2263/27744.

Full text

Abstract:

The rhodophytes or red seaweeds are an ancient group of organisms that are related to plants. Like terrestrial plants, they use secondary compounds to protect themselves from microbial infection and grazing by herbivores. However, unlike terrestrial plants, they produce mostly halogenated secondary compounds and rarely alkaloids. Osmundaria serrata (Rhodophyta) is found along the eastern South African coast and the Maldive Islands. Its descriptive common name is “red spirals” and the species is adapted to live in habitats with high wave action. Extracts from this seaweed had previously shown to have antimicrobial activity, but ecologically irrelevant microbes were used to test the extracts. In this study, ten bacteria were isolated from the surface of O. serrata and its habitat, and identified. Mostly aerobic and Gram-negative bacteria were isolated (Halomonas and Pseudomonas species) along with facultatively anaerobic forms (Vibrio spp.) and a Gram-positive (Marinococcus sp.). These were used in bioassays to compare the activity of extracts made from O. serrata and other seaweeds that occur in the same habitat. Marine bacteria are the initial colonizers in biofilm formation and subsequent fouling of surfaces in marine environments. The study of these bacteria in relation to their macroalgal hosts may help to control biofouling of surfaces that cause economic losses worldwide. A comparison was made between using agar dilution and microtitre methods for testing the antibacterial activity of an O. serrata extract. The microtitre method was found to be more sensitive than the agar dilution method. Possibly because e some of the bacteria on the petri plates (in the agar dilution method) were not in direct contact with the toxicant in the growth medium, but were in direct contact in the liquid medium of the wells in the microtitre plates. The extract from 0. serrata was the most active of the thirteen species of macroalgae collected from the same habitat and tested for antibacterial activity. Deformities in bacteria were observed in response to the 0. serrata extract. Increased capsule production and blebbing of the outer membranes were observed by transmission electron microscopy (negative staining). Lanosol diethyl ether was isolated from 0. serrata and tested for antibacterial activity. Lanosol is produced mainly by the rhodophytes, but it is also found in other macroalgae and fungi in lower concentrations. The compound inhibited the test bacteria with average MIC's of 0.27 ± 0.07 mg.mr1 (bacteriostatic) and 0.69 ± 0.15 mg.mr1 (bactericidal). Different forms of biofilm were observed by scanning electron microscopy on the thirteen species of macroalgae. These ranged from a very little biofilm covering on the calcified reds to complex communities on the other macroalgae. The treatment with OS04 vapour before fixation in glutaraldehyde preserved the biofilm structure better than no treatment and indicated that lipids are important in maintaining biofilm structure. Since a complex biofilm community was seen on the surface of 0. serrata, it is unlikely that lanosol functions as an antifouling agent. This chemical seems to multifunctional with antimicrobial and feeding deterrent activities. Thesis (PhD (Botany))--University of Pretoria, 2006. Plant Science unrestricted

APA, Harvard, Vancouver, ISO, and other styles

36

Lai, Yi-Show, and 賴意繡. "Isolation and characterization of DNA damage-recognition proteins expressed in the unicellular alga Chlorella pyrenoidosa and zebrafish (Danio rerio) embryos." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/20839970035886835277.

Full text

Abstract:

博士 國立臺灣海洋大學 生物科技研究所 93 Abstract Ultraviolet (UV) light is a component of the solar spectrum and UV penetrating from atmosphere into water is known to damage aquatic organisms present in the water surface layer. At the molecular level, UV irradiation significantly distorts the helical structure of DNA due to the formation of dipyrimidine photoproducts between two adjacent pyrimidines. To avoid producing error-prone replication or transcriptional blockage, UV-damaged DNA in most organisms is repaired primarily by excision-dependent pathways and DNA mismatches are corrected by mismatch repair. DNA repair pathways involving multipolypeptides are generally initiated by the binding of DNA damaged-recognition proteins to lesion sites. The unicellular alga Chlorella pyrenoidosa and zebrafish (Danio rerio) at fast-growing or early developmental stages are selected in this dissertation as the model systems for aquatic organisms to study proteins binding preferentially to DNA mispairs or dipyrimidine photoproducts. A duplex probe carrying a single G-T mispair was revealed by EMSA as a better binding target than those carrying other types of mispair for DNA mismatch recognition proteins in C. pyrenoidosa extracts. Two 13-kDa G-T binding polypeptides possessing pIs of 5.3 and 5.5 were isolated after resolving affinity-captured proteins by 2-D gel electrophoresis and the two factors were found to bind 5.5- and 2.8-fold stronger to heteroduplex than to homoduplex DNA, respectively. No proteins significantly homologous to the two algal G-T binding proteins were found by peptide mass fingerprinting (PMF). The sequence of a peptide generated from trypsin-cleavage of one G-T binding factor (pI 5.5) could be aligned with the amino acid sequences that form the C-terminal active sites of human and mouse mismatch-specific uracil/thymine-DNA glycosylases, suggesting the possibility of this factor as an algae- or a Chlorella-specific DNA mismatch glycosylase. UV-damaged-DNA binding activities in C. pyrenoidosa extracts recognizing both CPDs and 6-4PPs were also detected by EMSA. A 70-kDa polypeptide binding preferentially to a duplex probe carrying CPDs and 6-4PPs was pulled down from the algal extracts by affinity adsorption. Apparently higher levels of three 60 to 62-kDa polypeptides were eluted by 0.12% SDS from UV-irradiated than from unirradiated DNA immobilized on agarose beads when affinity-captured proteins were analyzed by 2-D gel electrophoresis. The 70-kDa polypeptide observed by SDS-PAGE might be an accumulation of these 60 to 62-kDa binding factors. Each SDS-eluted UV-binding polypeptide was found to bind 2 to 5-fold stronger to irradiated than to unirradiated DNA. None of the algal binding factors displayed significant sequence homology with proteins contained in the Mascot data base. Although algal proteins having higher affinities for mismatched or UV-damaged DNA were successfully isolated from C. pyrenoidosa extracts, little progress in protein identification was achieved because of the extremely low homology between algal DNA damage-recognition proteins and proteins already identified. The extracts of zebrafish (Danio rerio) early embryos and early larvae were found to contain different DNA damage-recognition proteins. Immunoblot analysis of proteins captured by agarose beads carrying a UV-irradiated duplex oligonucleotide revealed the presence of XPA in the extracts of 84-hr-old larvae, while no proteins homologous to those associated with human NER could be found in the extracts of 12-hr-old embryos. Incubation of the extracts of zebrafish embryos with a probe containing a 6-4PP produced high-shifting gel retardation complexes and participation of zebrafish vitellogenin 1(Vg1)-like proteins in generating the UV-binding activity was revealed by mass spectrometric analysis of proteins contained in the binding complexes. The binding of 12-hr old zebrafish extracts to 6-4PPs was inhibited to 60% of control by the addition of a rabbit anti-carp Vg antiserum to gel shift assay mixtures. UV-damaged-DNA binding proteins synthesized in zebrafish embryos could be efficiently separated from nonspecific DNA binding proteins by a preparative isoelectrofocusing. Nonspecific binding proteins were collected at pH from 4 to 6, yet the majority of zebrafish proteins binding preferentially to 6-4PPs were found to possess pIs about 7 to 9 and proteins displaying the strongest UV-dependent binding were isoelectrofocused between pH from 7 to 8. Four 25-kDa polypeptides having pIs between 7.3 to 7.8 were thought to be important damage-recognition factors after comparing 2-D polypeptide patterns produced by protein fractions showing strong, moderate, low and no UV-specific binding activity. Although the four polypeptides were not binding targets for a monoclonal anti-zebrafish Vg1 antibody, they all contained amino acid sequences LPIIVTTYAK and IPEITMSK which also appear in the C-terminal Lv2 region of zebrafish Vg1 according to tandem mass spectrometry(MS/MS). One 25-kDa polypeptide possessing a pI about 7.4 was shown to bind strongly to UV-damaged DNA after affinity adsorption of the active protein fraction with a 6-4PP probe and some Lv2 sequences present in other 25-kDa polypeptides were missing in this UV-binding factor. Since several 100 to 25 kDa Vtg1-like proteins produced in 12 to 96-hr-old zebrafish could be detected by the anti-zebrafish Vg1 antibody, the four 25-kDa polypeptides totally unreactive to the same antibody suggested that they originated from a source unrelated to proteolytic degradation of Vg1. The four 25-kDa polypeptides were also identified as phosphoproteins, but not glycoproteins, according to selective protein staining. The original zebrafish Vg1 having a molecular mass of 150 kDa is a metalloprotein whose degradation during developmental process is known to provide amino acids and essential metals for growing embryos. Our results revealed the identification of a group of novel embryonic proteins highly homologous to the Lv2 region of Vg1 and one low-molecular-weight Vg1-like protein might participate in DNA repair or recombination based on its preferential binding to UV-damaged DNA.

APA, Harvard, Vancouver, ISO, and other styles

37

Cosentino, Emanuela. "Optimization of High and Ultra High Molecular Weight DNA purification for Third Generation Sequencing and Optical Mapping in algae." Doctoral thesis, 2020. http://hdl.handle.net/11562/1018425.

Full text

Abstract:

The analysis of long DNA molecules by novel genomic technologies, such as Bionano optical mapping and Third Generation Sequencing, including PacBio Single Molecule Real Time Sequencing and Oxford Nanopore sequencing, provide the opportunity for complete genome characterization and reconstruction, allowing to identify large (balanced) structural variants, to determine the variant phasing and haplotype, to sequence full-length repeated regions and to assemble and scaffold genomes de-novo. Implementation of these technologies requires a combination of highly pure and High Molecular Weight (HMW) DNA, >10^5bp (Bionano Optical Mapping) or >10^4bp (Third Generation Sequencing) in length. However, standardized and suitable extraction methods to obtain highly pure HMW DNA are still missing for many organisms and tissues. In particular, plants and algae store a large amount of phenolic compounds, polysaccharides and a high copy number of chloroplast and mitochondrial DNA, making the extraction of both pure and HMW genomic DNA challenging. The aim of this work was the optimization of methods for the purification of highly pure and (Ultra)HMW DNA from a microalgae selected as case study, Haematococcus pluvialis (H.pluvialis), suitable for Third Generation sequencing and Bionano optical mapping. Despite H.pluvialis is unicellular green microalgae extensively studied for industrial applications, a high quality genome for its biotechnological application is still missing. Therefore, an extensive benchmarking of DNA and nuclei isolation methods was conducted to produce high-quality HMW DNA suitable to generate Third Generation sequencing and Bionano optical mapping data for the reconstruction of its genome de-novo. 4 (U)HMW DNA extraction methods and 8 nuclei isolation methods and 4 post-extraction DNA purification methods were evaluated independently or in combination. To further improve DNA purity and optimize the production of high-quality sequencing data, 4 post-extraction DNA purification methods were also tested. The methods were compared in terms of yield, length and purity of extracted DNA and its analysis by Third Generation sequencing and optical mapping. Only 3 specific combinations of these protocols yielded suitable DNA to generate successful results with PacBio (CTAB buffer+AMPureXP beads purification), Oxford Nanopore (MEB buffer+G-tip- DNA based extraction) and Bionano (MEB buffer+plug- DNA based extraction). The data produced herein can be used to obtain a highly contiguous genome for H.pluvialis with the efficient reconstruction of repetitive genomic portions (highly present in H.pluvialis genome), by eliminating ambiguity in the positions or size of genomic elements.

APA, Harvard, Vancouver, ISO, and other styles

38

Abdelaziz, Ahmed EM. "Isolation and identification of native microalgae for biodiesel production." Thèse, 2014. http://hdl.handle.net/1866/10908.

Full text

Abstract:

La demande croissante en carburants, ainsi que les changements climatiques dus au réchauffement planétaire poussent le monde entier à chercher des sources d’énergie capables de produire des combustibles alternatifs aux combustibles fossiles. Durant les dernières années, plusieurs sources potentielles ont été identifiées, les premières à être considérées sont les plantes oléagineuses comme source de biocarburant, cependant l’utilisation de végétaux ou d’huiles végétales ayant un lien avec l’alimentation humaine peut engendrer une hausse des prix des denrées alimentaires, sans oublier les questions éthiques qui s’imposent. De plus, l'usage des huiles non comestibles comme sources de biocarburants, comme l’huile de jatropha, de graines de tabac ou de jojoba, révèle un problème de manque de terre arable ce qui oblige à réduire les terres cultivables de l'industrie agricole et alimentaire au profit des cultures non comestibles. Dans ce contexte, l'utilisation de microorganismes aquatiques, tels que les microalgues comme substrats pour la production de biocarburant semble être une meilleure solution. Les microalgues sont faciles à cultiver et peuvent croitre avec peu ou pas d'entretien. Elles peuvent ainsi se développer dans des eaux douces, saumâtres ou salées de même que dans les terres non cultivables. Le rendement en lipide peut être largement supérieur aux autres sources de biocarburant potentiel, sans oublier qu’elles ne sont pas comestibles et sans aucun impact sur l'industrie alimentaire. De plus, la culture intensive de microalgues pour la production de biodiesel pourrait également jouer un rôle important dans l'atténuation des émissions de CO2. Dans le cache de ce travail, nous avons isolé et identifié morphologiquement des espèces de microalgues natives du Québec, pour ensuite examiner et mesurer leur potentiel de production de lipides (biodiesel). L’échantillonnage fut réalisé dans trois régions différentes du Québec: la région de Montréal, la gaspésie et le nord du Québec, et dans des eaux douces, saumâtres ou salées. Cent souches ont été isolées à partir de la région de Montréal, caractérisées et sélectionnées selon la teneur en lipides et leur élimination des nutriments dans les eaux usées à des températures différentes (10 ± 2°C et 22 ± 2°C). Les espèces ayant une production potentiellement élevée en lipides ont été sélectionnées. L’utilisation des eaux usées, comme milieu de culture, diminue le coût de production du biocarburant et sert en même temps d'outil pour le traitement des eaux usées. Nous avons comparé la biomasse et le rendement en lipides des souches cultivées dans une eau usée par apport à ceux dans un milieu synthétique, pour finalement identifié un certain nombre d'isolats ayant montré une bonne croissance à 10°C, voir une teneur élevée en lipides (allant de 20% à 45% du poids sec) ou une grande capacité d'élimination de nutriment (>97% d'élimination). De plus, nous avons caractérisé l'une des souches intéressantes ayant montré une production en lipides et une biomasse élevée, soit la microalgue Chlorella sp. PCH90. Isolée au Québec, sa phylogénie moléculaire a été établie et les études sur la production de lipides en fonction de la concentration initiale de nitrate, phosphate et chlorure de sodium ont été réalisées en utilisant de la méthodologie des surfaces de réponse. Dans les conditions appropriées, cette microalgue pourrait produire jusqu'à 36% de lipides et croitre à la fois dans un milieu synthétique et un milieu issu d'un flux secondaire de traitement des eaux usées, et cela à 22°C ou 10°C. Ainsi, on peut conclure que cette souche est prometteuse pour poursuivre le développement en tant que productrice potentielle de biocarburants dans des conditions climatiques locales. The continuing increase in fuel demands, the dramatic situation in climate changes and the global warming are bringing the worldwide attention to the identification of alternative energy source for the production of combustibles that can replace fossil fuel. In last years, a lot of potential sources have been identified: the first potential biofuel feedstock that have been evaluated were oleaginous plants, but the utilization of vegetable, or vegetable oils, that may also be used for human feeding, could lead to the increase of food-grade oils costs and also generate ethic questions. Nevertheless, also using as biofuel sources not-edible oils, like oils from jatropha, tobacco seed or jojoba, the common problem for both edible and not-edible crops is the need to subtract arable land from agriculture and food industry. In this context, the utilization of aquatic microorganisms like microalgae as substrate for the production of biofuel seems to be the better solution. Microalgae are easy to cultivate and can grow with little or no attention, they can grow in fresh, brackish or salt water and in non-arable lands, moreover they are not edible with no consequences on food industry, and the oil productivity, with respect to the other potential biofuel sources, can be much higher. In addition, the intensive cultivation of microalgae for biodiesel production could also play an important role in CO2 mitigation. In this study, we isolated and morphologically identified Québec native micro algal species, surveyed and screened their potential for lipid (biodiesel) production. The sampling efforts made in three different regions of Québec: Montreal area, Gaspesie and Northern of Quebec; on fresh, brackish or saline water. One hundred strains were isolated from the Montreal area, characterized and screened for their lipid content and wastewater nutrient removal under different temperatures (10±2 ºC and 22±2 ºC). The high potential lipid producing algal species were selected. The use of wastewater as a substrate media decreases the economic cost realted to the biofuel production from microalgae as well as an interesting tool for wastewater treatment. We compared the biomass and lipid productivity of these strains on wastewater to a synthetic medium and identified a number of isolates that showed good growth at 10 ºC, gave a high lipid content (ranging from 20% to 45% of dry weight) or a high capacity for nutrient removal (>97% removal). Furthermore, we characterized one of the interesting strains that revealed high lipid and biomass productivity, the novel microalga Chlorella sp. PCH90. Its molecular phylogeny was established and lipid production studies as a function of the initial concentrations of nitrate, phosphate, and sodium chloride were carried out using Response Surface Methodology. Under the appropriate conditions this microalga could produce up to 36% lipid and grew well in both synthetic medium and secondary effluent from a wastewater treatment plant at both 22°C and 10°C. Thus, this strain is promising for further development as a potential biofuels producer under local climatic conditions.

APA, Harvard, Vancouver, ISO, and other styles

39

Abdelaziz, Ahmed E. M. "Isolation and identification of native microalgae for biodiesel production." Thèse, 2014. http://hdl.handle.net/1866/10908.

Full text

Abstract:

La demande croissante en carburants, ainsi que les changements climatiques dus au réchauffement planétaire poussent le monde entier à chercher des sources d’énergie capables de produire des combustibles alternatifs aux combustibles fossiles. Durant les dernières années, plusieurs sources potentielles ont été identifiées, les premières à être considérées sont les plantes oléagineuses comme source de biocarburant, cependant l’utilisation de végétaux ou d’huiles végétales ayant un lien avec l’alimentation humaine peut engendrer une hausse des prix des denrées alimentaires, sans oublier les questions éthiques qui s’imposent. De plus, l'usage des huiles non comestibles comme sources de biocarburants, comme l’huile de jatropha, de graines de tabac ou de jojoba, révèle un problème de manque de terre arable ce qui oblige à réduire les terres cultivables de l'industrie agricole et alimentaire au profit des cultures non comestibles. Dans ce contexte, l'utilisation de microorganismes aquatiques, tels que les microalgues comme substrats pour la production de biocarburant semble être une meilleure solution. Les microalgues sont faciles à cultiver et peuvent croitre avec peu ou pas d'entretien. Elles peuvent ainsi se développer dans des eaux douces, saumâtres ou salées de même que dans les terres non cultivables. Le rendement en lipide peut être largement supérieur aux autres sources de biocarburant potentiel, sans oublier qu’elles ne sont pas comestibles et sans aucun impact sur l'industrie alimentaire. De plus, la culture intensive de microalgues pour la production de biodiesel pourrait également jouer un rôle important dans l'atténuation des émissions de CO2. Dans le cache de ce travail, nous avons isolé et identifié morphologiquement des espèces de microalgues natives du Québec, pour ensuite examiner et mesurer leur potentiel de production de lipides (biodiesel). L’échantillonnage fut réalisé dans trois régions différentes du Québec: la région de Montréal, la gaspésie et le nord du Québec, et dans des eaux douces, saumâtres ou salées. Cent souches ont été isolées à partir de la région de Montréal, caractérisées et sélectionnées selon la teneur en lipides et leur élimination des nutriments dans les eaux usées à des températures différentes (10 ± 2°C et 22 ± 2°C). Les espèces ayant une production potentiellement élevée en lipides ont été sélectionnées. L’utilisation des eaux usées, comme milieu de culture, diminue le coût de production du biocarburant et sert en même temps d'outil pour le traitement des eaux usées. Nous avons comparé la biomasse et le rendement en lipides des souches cultivées dans une eau usée par apport à ceux dans un milieu synthétique, pour finalement identifié un certain nombre d'isolats ayant montré une bonne croissance à 10°C, voir une teneur élevée en lipides (allant de 20% à 45% du poids sec) ou une grande capacité d'élimination de nutriment (>97% d'élimination). De plus, nous avons caractérisé l'une des souches intéressantes ayant montré une production en lipides et une biomasse élevée, soit la microalgue Chlorella sp. PCH90. Isolée au Québec, sa phylogénie moléculaire a été établie et les études sur la production de lipides en fonction de la concentration initiale de nitrate, phosphate et chlorure de sodium ont été réalisées en utilisant de la méthodologie des surfaces de réponse. Dans les conditions appropriées, cette microalgue pourrait produire jusqu'à 36% de lipides et croitre à la fois dans un milieu synthétique et un milieu issu d'un flux secondaire de traitement des eaux usées, et cela à 22°C ou 10°C. Ainsi, on peut conclure que cette souche est prometteuse pour poursuivre le développement en tant que productrice potentielle de biocarburants dans des conditions climatiques locales. The continuing increase in fuel demands, the dramatic situation in climate changes and the global warming are bringing the worldwide attention to the identification of alternative energy source for the production of combustibles that can replace fossil fuel. In last years, a lot of potential sources have been identified: the first potential biofuel feedstock that have been evaluated were oleaginous plants, but the utilization of vegetable, or vegetable oils, that may also be used for human feeding, could lead to the increase of food-grade oils costs and also generate ethic questions. Nevertheless, also using as biofuel sources not-edible oils, like oils from jatropha, tobacco seed or jojoba, the common problem for both edible and not-edible crops is the need to subtract arable land from agriculture and food industry. In this context, the utilization of aquatic microorganisms like microalgae as substrate for the production of biofuel seems to be the better solution. Microalgae are easy to cultivate and can grow with little or no attention, they can grow in fresh, brackish or salt water and in non-arable lands, moreover they are not edible with no consequences on food industry, and the oil productivity, with respect to the other potential biofuel sources, can be much higher. In addition, the intensive cultivation of microalgae for biodiesel production could also play an important role in CO2 mitigation. In this study, we isolated and morphologically identified Québec native micro algal species, surveyed and screened their potential for lipid (biodiesel) production. The sampling efforts made in three different regions of Québec: Montreal area, Gaspesie and Northern of Quebec; on fresh, brackish or saline water. One hundred strains were isolated from the Montreal area, characterized and screened for their lipid content and wastewater nutrient removal under different temperatures (10±2 ºC and 22±2 ºC). The high potential lipid producing algal species were selected. The use of wastewater as a substrate media decreases the economic cost realted to the biofuel production from microalgae as well as an interesting tool for wastewater treatment. We compared the biomass and lipid productivity of these strains on wastewater to a synthetic medium and identified a number of isolates that showed good growth at 10 ºC, gave a high lipid content (ranging from 20% to 45% of dry weight) or a high capacity for nutrient removal (>97% removal). Furthermore, we characterized one of the interesting strains that revealed high lipid and biomass productivity, the novel microalga Chlorella sp. PCH90. Its molecular phylogeny was established and lipid production studies as a function of the initial concentrations of nitrate, phosphate, and sodium chloride were carried out using Response Surface Methodology. Under the appropriate conditions this microalga could produce up to 36% lipid and grew well in both synthetic medium and secondary effluent from a wastewater treatment plant at both 22°C and 10°C. Thus, this strain is promising for further development as a potential biofuels producer under local climatic conditions.

APA, Harvard, Vancouver, ISO, and other styles

40

Heidelberger, Gero [Verfasser]. "Untersuchung von"high-k" Materialien als alternative Dielektrika für AlGaN/GaN-basierte Metall-Isolator-Halbleiter-Heterostruktur-Feldeffekt-Transistoren (MISHFET) = Investigation of "high-k" materials as alternative dielectrics for AlGaN/GaN-based metal-insulator-semiconductor heterostructure field effect transistors (MISHFET) / vorgelegt von Gero Heidelberger." 2009. http://d-nb.info/996800182/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Algal isolation'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles