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Cazelles, B., and D. Fontvieille. "Modélisation d'un système lotique pollué par une charge organique : prise en compte de l'activité des microorganismes benthiques." Revue des sciences de l'eau 2, no. 4 (April 12, 2005): 511–41. http://dx.doi.org/10.7202/705041ar.
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Les études entreprises depuis 1982 sur un petit cours d'eau pollué par une forte charge organique, ont servi de base au développement d'un modèle mathématique destiné à appréhender le fonctionnement des mécanismes d'auto-épuration. L'écriture du modèle a débuté par la description de l'écoulement du cours d'eau et des mécanismes de transports associés. Deux sous-modèles ont été utilisés dans ce but : un sous-modèle hydrodynamique dérivé du modèle de Saint-Venant et un sous-modèle de transport, constitué par l'équation classique de convection-dispersion. Ces deux sous-modèles sont appliqués à un écoulement monodimensionnel, non uniforme et non stationnaire. Dans les petits cours d'eau le compartiment benthique joue un rôle prépondérant du point de vue de l'ensemble des processus détritiques. Le modèle a donc été appliqué, dans un premier temps, à la simulation de la dynamique du carbone organique dissous et des microorganismes benthiques. Les mécanismes de biodégradation sont modélisés, ici, en utilisant l'analogie entre les processus détritiques et l'activité des biomasses des procédés de traitement des eaux usées. Le modèle de biofilm développé permet, par sa structure, d'englober tous les mécanismes physiques et biologiques qui entrent dans les phénomènes de disparition et de dégradation de la matière organique dissoute. Ce modèle est utilisé, sous sa forme actuelle, en tant qu'outil cognitif destiné à accroître la connaissance des mécanismes d'auto-épuration de la matière organique dissoute dans les petits cours d'eau.
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Pesce, Stéphane. "Adaptation des microorganismes à la contamination environnementale par les substances pharmaceutiques : quelles conséquences sur la dispersion de l’antibiorésistance dans les écosystèmes ?" Revue Neurologique 180 (April 2024): S176. http://dx.doi.org/10.1016/j.neurol.2024.02.345.
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Iakovchenko, N. V., and M. A. Antsyperova. "Perspective of probiotic bacteria in the production of soy-based fermented products." Agrarian science, no. 3 (March 25, 2024): 149–56. http://dx.doi.org/10.32634/0869-8155-2024-380-3-149-156.
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Relevance. It is worth noting that consumers’ awareness of the environmental burden that milk production carries continues to grow. Consumers are looking for alternatives that are more environmentally friendly and have high nutritional value. The demand for plant-based products is increasing for various reasons, namely, 65% of the world’s population has a reduced ability to digest lactose and 6% of the population is allergic to milk protein. According to statistics, 49% of women and 36.6% of men experience symptoms of functional gastrointestinal disorders. Soybeans are one of the most widely grown and consumed legumes worldwide. Thus, the development of new plant-based fermented products is a particularly actual issue.Methods. The objects of study were soybean dispersion and microorganisms Lactobacillus, Bifidobacterium and Propionibacterium. The quality indicators of the resulting soy dispersion were determined. The process of acid accumulation during fermentation with probiotic microorganisms were studied. Data on the accumulation of bacterial biomass during the fermentation process were obtained and the effect of the use of selected starter microorganisms on the change in the antioxidant status of fermented dispersions during storage were investigated.Results. Research results showed that soybean dispersion is a good substrate to produce fermented beverages using Lactobacillus, Bifidobacterium and Propionibacterium microorganisms. The most rapid process occurs when L. bulgaricus and P. schermanii KM-186 are used and the fermentation lasted for 6 hours. All selected strains adapt well to the plant-based media, but the greatest increase in biomass occurs during fermentation with L. bulgaricus, B. longum B379M and B. bifidum. Lactic acid and propionic acid bacteria provide high and stable levels of antioxidant activity on both the 1st and 6th and 12th days of storage.
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Zhukova, Irina V., Azat A. Girfanutdinov, Bulat F. Gataullin, Ksenia V. Golovanova, Tatiana V. Vdovina, Rozalia F. Akchurina, and Alexander A. Tabachkov. "Investigation of antibacterial resistance of aliphatic quarterly ammonium salts in polyrethane dispersions." Butlerov Communications 57, no. 3 (March 31, 2019): 128–32. http://dx.doi.org/10.37952/roi-jbc-01/19-57-3-128.
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In this work we investigated the possibility of using different structures of biocides to detect the stability of dispersion and the antibacterial properties of polyurethane water-dispersion coatings to combat the negative impact on materials, bio-damage, which can affect the quality of the human environment. This allows the use of polyurethane aqueous dispersions, where the constancy of aseptic conditions of quality is combined with good properties of polyurethane coatings. The oasheaters have been used in the first year of the 19th century to reduce the number of people. Coatings used dispe6rsionnye water-based polyurethane dispe6rsii complex poliefrov different structure (polietilenglikoladipinat, polietilenbutilenglikoladipinat, and polibutilenglikoladipinat polidietilenglikoladipinat) 2,4-diisocyanate, ionic agent and chain extenders, at a concentration of dry matter of 20-50% by weight. One of the most commonly used methods for determining the activity of antimicrobial agents is the method of diffusion of substances into agar. Evaluation of the activity of antimicrobial agents by this method is carried out according to the diameter of the zone of inhibition of growth of microorganisms (Escherichia Colli and Bacillus subtilis) on the surface of the substrate. As a result of the research, it was revealed that the actions of the used antimicrobial agents can be arranged in the following order: alkyltrimethylammonium chloride > didecyldimethylammonium chloride > dialkyldimethylammonium chloride. Maximum concentrations of biocides were found at which polyurethane dispersions are stable and do not coagulate: for quaternary amine compounds with one alkyl, the maximum permissible concentration is 10%, with dialkyl the maximum permissible concentration is 7.5%, with trialkyl the maximum permissible concentration is 3%. The increase in the diameter of the suppression of the growth of microorganisms is also influenced by the concentration of the polyurethane dispersion, which makes it possible to introduce antibacterial compounds much more.
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Ishikawa, Takuji. "Vertical dispersion of model microorganisms in horizontal shear flow." Journal of Fluid Mechanics 705 (April 13, 2012): 98–119. http://dx.doi.org/10.1017/jfm.2012.116.
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AbstractMicroorganisms often swim upwards due to the cell’s phototaxis, chemotaxis or geotaxis, in flow fields with vertical velocity gradients. In this study, the vertical dispersion of model microorganisms was investigated under horizontal shear conditions. A microorganism was modelled as a spherical squirmer with or without bottom-heaviness. First, the three-dimensional movement of 100 identical squirmers in a homogeneous suspension was computed by the Stokesian dynamics method. The results show that the dispersion of squirmers is strongly affected by the swimming velocity and bottom-heaviness of the cells and the shear rate of the background flow. The vertical diffusion is considerably smaller than the horizontal diffusion. Interestingly, the vertical diffusion decreases as the volume fraction and the stresslet of squirmers decrease, which is opposite of the tendency in diffusion with no background flow. Next, a continuum model of a suspension of squirmers was developed using the diffusion tensor and the drift velocity to simulate the spatial distribution of squirmers in macroscopic flow fields. The results of the continuum model illustrate that the gyrotactic trapping found by Durham, Kessler & Stocker (Science, vol. 323, 2009, pp. 1067–1070) also appears in the present model considering cell–cell hydrodynamic interactions. In the case of horizontal Poiseuille flow, the volume fraction of bottom-heavy cells in the channel becomes considerably larger than that at the inlet. These fundamental findings are helpful for understanding the distribution of microorganisms in various water regimes in nature and industry.
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Дмитриева, Елена Дмитриевна, and Мария Михайловна Герцен. "INFLUENCE OF PEATS HUMIC SUBSTANCES ON THE STATE OF DROPS OF CRUDE OIL AND OIL PRODUCTS IN THE PRESENCE OF OIL DEGRADING MICROORGANISMS OF THE GENUS RHODOCOCCUS." Вестник Тверского государственного университета. Серия: Химия, no. 2(44) (June 25, 2021): 69–79. http://dx.doi.org/10.26456/vtchem2021.2.7.
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Максимальное диспергирование капель модельных нефтепродуктов в присутствии микроорганизмов Rhodococcus erythropolis X5 и гуминовых кислот сфагнового верхового торфа, а также микроорганизмов Rhodococcus erythropolis S67 и гуминовых кислот тростникового низинного торфа. Проведенный экспресс-тест доказал, что уменьшение пленки нефтепродуктов может быть использовано для проверки диспергирующей способности микроорганизмов Rhodococcus X5 или S67 и молекул гуминовых кислот. Установлено, что биокомпозиция на основе гуминовых кислот и микроорганизмов-нефтедеструкторов рода Rhodococcus способна адсорбироваться на границе раздела нефть-вода, переводя нефть в водную толщу, где она разлагается микроорганизмами-нефтедеструкторами. Maximum dispersion of droplets of model petroleum products has been observed in the presence of microorganisms Rhodococcus erythropolis X5 and humic substances of sphagnum high-moor peat, and microorganisms Rhodococcus erythropolis S67 and humic substances of reed fen peat. The express test proved that the reduction of the oil sheen can be used to the test the dispersing ability of microorganisms Rhodococcus X5 or S67 and humic substances. It has been established that a biocomposition based on humic substances and oil degrading microorganisms of the genus Rhodococcus is capable of adsorbing at the oil-water interface, transferring oil into the water column, where it is decomposed by oil degrading microorganisms.
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Reponen, Tiina, Klaus Willeke, Vidmantas Ulevicius, Sergey A. Grinshpun, and Jean Donnelly. "Techniques for Dispersion of Microorganisms into Air." Aerosol Science and Technology 27, no. 3 (September 1997): 405–21. http://dx.doi.org/10.1080/02786829708965481.
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Kaiyrmanova, Gulzhan, Aelina Abitbekova, Ulzhan Shaimerdenova, Alisher Asylbek, and Aliya Yernazarova. "Oil dispersion characterization of microorganisms producing biosurfactants." BIO Web of Conferences 100 (2024): 02018. http://dx.doi.org/10.1051/bioconf/202410002018.
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The article is dedicated to studying the ability of crude oil emulsification and displacement by bacteria producing low-molecular-weight biosurfactants. Six hydrocarbon-oxidizing cultures of microorganisms were used in this study: 3 strains of Pseudomonas aeruginosa (T1, T4, D2) and 3 Bacillus cultures: Bacillus licheniformis A3, Bacillus subtilis subsp. subtilis A12, Bacillus subtilis A9 from the collection of the Biotechnology Department of Al-Farabi Kazakh National University. The research findings indicate that cells of P. aeruginosa T1 exhibited maximum emulsifying and displacing properties, with an E24 value of 76.4% and an oil displacement ability of 5.1 cm. Among the three genes responsible for the production of low-molecular-weight biosurfactants, the presence of one gene, rhlA, responsible for the synthesis of rhamnolipid biosurfactants, has been confirmed. It was demonstrated that strains P. aeruginosa T1, P. aeruginosa T4, B. subtilis A9, and B. subtilis subsp. subtilis A12 showed high emulsifying activity, making them potentially effective for application in biotechnological processes aimed at enhancing oil recovery from mature reservoirs and in bioremediation processes.
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Gelazov, R. Kh, N. V. Iakovchenko, K. R. Bayazitov, and V. A. Shiriaev. "Prospects for the use of probiotic microorganisms in the production of fermented buckwheat-based products." Agrarian science, no. 4 (April 25, 2024): 138–45. http://dx.doi.org/10.32634/0869-8155-2024-381-4-138-145.
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Relevance. The market segment for products based on plant-based ingredients continues to gain momentum. Protecting health and reducing the environmental burden are the most important driving forces for consumers to buy plant-based products. About 1% of the world’s population suffers from diagnosed celiac disease. Around 13% of the population exhibits symptoms of non-celiac gluten sensitivity. Thus, the production of gluten-free food products, including fermented ones, is becoming increasingly important.Methods. The technological parameters for producing buckwheat dispersion and its quality indicators were assessed. The analysis of the process of acid accumulation during fermentation by microorganisms Lactobacillus, Bifidobacterium, Propionibacterium, and Streptococcus was carried out. Data on the dynamics of microbial biomass accumulation during fermentation were obtained, and the influence of selected starter cultures on the antioxidant properties of fermented dispersions during storage was studied. The impact of chosen strains on organoleptic characteristics was determined, and the dependence of the viscosity of fermented samples on the shear rate was studied.Results. Buckwheat dispersion is a suitable medium for the production of fermented drinks. The duration of fermentation ranged from 5 to 9 hours. The most intense acid accumulation process is observed when S. thermophilus is used for 5 hours. The maximum increase in biomass is achieved with L. bulgaricus, L. acidophilus AT-41, and B. bifidum. Probiotic microorganisms provide stable levels of antioxidant activity during storage. The samples fermented with S. thermophilus, B. bifidum, P. shermanii KM-186, and L. bulgaricus were the most viscous. The most outstanding organoleptic preference was given to samples with L. acidophilus 57S, S. thermophilus, and L. bulgaricus.
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Sommerauer, Lukas, Alexander Petutschnigg, and Thomas Schnabel. "Investigation of Impregnation Approach of Zinc Oxide Nano-Dispersions for Potential UV Stabilization in Abies alba and Fagus sylvatica." Compounds 3, no. 4 (November 1, 2023): 561–72. http://dx.doi.org/10.3390/compounds3040040.
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As biological material, wood is distinctly affected by to various environmental influences during use. Reductions in durability can come from ultraviolet (UV) radiation, insects, fungi, and microorganisms in both exterior and interior applications. Wood can be easily protected from living organisms via the control of moisture content; however, UV radiation is not so easily managed. Wood components subject to this degradation are damaged and decomposed at a molecular level leading to deterioration of surface quality, especially in visible application areas. A potential remedy to this is using the UV-stabilizing properties of zinc oxide nanoparticles. Zinc oxide nano-dispersions based on propylene glycol (PG) were introduced into the microscopic structure of fir (Abies alba) and beech (Fagus sylvatica) wood by whole-cell impregnation to overcome problems associated with surface coatings. In this work the material uptake of ZnO nano-dispersions in concentrations of 1%, 2%, and 3% w/v were investigated and their effect on the stability of the optical appearance to UV exposure in short-term weathering were evaluated. Untreated reference samples showed significant photo-yellowing. A 1% w/v ZnO dispersion significantly increased the UV stability of treated surfaces. It was found that the uptake of the nano-dispersions was independent of the proportion of ZnO, and that the impregnating agents penetrated fir wood (about 200%) stronger than beech wood (about 70%). Already, a 2% w/v ZnO nano-dispersion led to a saturation of ZnO in the cell structure of the treated wood, for fir as well as beech, and no further ZnO uptake was achieved with 3% w/v nano-dispersions. Scanning electron microscopy shows an agglomeration of ZnO-NP in the cellular pathways impacting penetration, reducing leachability at higher concentrations.
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Lyalkova, N. N., and N. A. Yurkova. "Role of microorganisms in vanadium concentration and dispersion." Geomicrobiology Journal 10, no. 1 (January 1992): 15–26. http://dx.doi.org/10.1080/01490459209377901.
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Carbonero-Pacheco, Juan, José Aguilar, María Carmen Raya, Antonio Trapero, Miquel Gaju-Ricart, and Carlos Agustí-Brisach. "Diversity of Cellulolytic Microorganisms Associated with the Subterranean Termite Reticulitermes grassei." Journal of Fungi 9, no. 3 (February 24, 2023): 294. http://dx.doi.org/10.3390/jof9030294.
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Reticulitermes grassei is a subterranean termite species that forages on woody structures of the Iberian Peninsula, and is often a building and crops pest. A total of 23 microorganisms associated with the activity of R. grassei were isolated from colonized ecosystems in southern Spain. They were morphologically and molecularly characterized, with fungi being the most prevalent ones. The fungi showed high values of optimum growth temperature, suggesting that they could be able to survive and develop in warm regions. Their cellulolytic activity was tested in carboxymethylcellulose (CMC) agar, concluding that all fungal isolates produce cellulases, and the enzymatic index (EI) was revealed in CMC agar with Gram’s iodine solution, with Penicillium citrinum showing the highest EI and Trichoderma longibrachiatum the highest mycelial growth rate on CMC. A preliminary microorganism dispersion assay was carried out with the termites, concluding that these insects may have a positive influence on fungal dispersion and the subsequent colonization of new substrates. Our study suggests that fungi associated with R. grassei may potentially be of interest in biotechnological fields such as biofuel production and the food industry.
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Chilukuri, Sandeep, Cynthia H. Collins, and Patrick T. Underhill. "Dispersion of flagellated swimming microorganisms in planar Poiseuille flow." Physics of Fluids 27, no. 3 (March 2015): 031902. http://dx.doi.org/10.1063/1.4914129.
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Sánchez-Monedero, M. A., and E. I. Stentiford. "Generation and Dispersion of Airborne Microorganisms from Composting Facilities." Process Safety and Environmental Protection 81, no. 3 (May 2003): 166–70. http://dx.doi.org/10.1205/095758203765639861.
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Rittmann, B. E., and N. M. Johnson. "Rapid Biological Clean-Up of Soils Contaminated with Lubricating Oil." Water Science and Technology 21, no. 4-5 (April 1, 1989): 209–19. http://dx.doi.org/10.2166/wst.1989.0224.
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An experimental program assessed which mechanisms control the rapid biodegradation of used lubricating oil which contaminates soils. The ultimate goal is to effect a rapid biodegradation before the contaminants in the oil are leached into the groundwater or carried into surface waters with runoff. Large amounts of lubricating-oil-degrading bacteria could be grown in liquid culture, as long as a dispersant was applied to form and maintain an oil-in-water emulsion. Application of the oil-degrading bacteria (up to 4.9 × 108/g soil) significantly increased the initial rate of oil degradation in soil plots. However, the long-term rate of degradation slowed as the more available or more biodegradable components of the oil were removed. The fastest removal rates were obtained when the oil-contaminated soil was put into a water-soil slurry and was inoculated with microorganisms and dispersant. Improved microorganism contact and dispersant effectiveness apparently were responsible for the rapid rates in slurry reactors. The increased rates demonstrated the potential value of adding a large, acclimated inoculum and providing good mixing and dispersion to make the oil more available to the microorganisms.
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Usman, Yusnita. "PEMANFAATAN POTENSI LIMBAH KULIT BAWANG MERAH (Allium Cepa. L) SEBAGAI SEDIAAN GEL HAND SANITIZER." Jurnal Riset Kefarmasian Indonesia 2, no. 2 (May 1, 2020): 63–71. http://dx.doi.org/10.33759/jrki.v2i2.79.
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The increased health problems caused by microorganisms at the hands, hand sanitizer gel as the way out to maintained health and hand hygiene because it is more practical and easy to carry. The purpose of this study was to make formulations of gel with physically stable and had inhibitory activity against the Staphylococcus aureus bacteria. In this study three formulations were made with a ratio of Hydroxy ethyl selilulose 0.5% (F1), 1% (F2) and 2% (F3) then physical stability testing included organoleptic, homogeneity, pH and dispersion before and after accelerated storage, then antimicrobial activity by sump method. Organoleptic test showed there is no color, smell and texture changes. The results of the homogenety test, formula with concentration of Hydroxy ethyl cellulose 1% and 2% is homogeneous. The pH test results showed that the gel preparation did not change pH. Dispersing test showed concentration hydroxyethyl cellulose 1% has the highest dispersion value. but statistical paired T test results showed that the dispersion before and after storage was accelerated significantly different 0.043 (p <0.05), but still in accordance with the range of dispersion specifications for a good semisolid preparation.The MIC test results showed Formulation F1, F2 and F3 ethanol extract red onion skin gel are strong inhibitory effect, ethanol extract of red onion skin gel F1 inhibitory zone is 16mm, F2 and F3 had the same inhibitory zone is 14.33. It can be concluded F2 has the best physical stability, but F1 is the most effective to inhibit Staphylococcus aureus.
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Vogt, Kyra Atessa, and Iris Steinberg. "Impact of Dispersing on the Production and Extraction of Bio-Based Basic Chemicals from Biogenic Secondary Waste." Environmental and Climate Technologies 28, no. 1 (January 1, 2024): 490–99. http://dx.doi.org/10.2478/rtuect-2024-0038.
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Abstract Biogenic waste from waste treatment plants, secondary waste, can be used to produce bio-based carboxylic acids, conventionally produced by chemical synthesis from petroleum-based feedstocks or by synthesis from natural oils. The cascading use of organic residues and wastes to produce bio-based products can contribute to the circular bioeconomy. In the process of biologically treating waste to produce bio-based carboxylic acids, microorganisms already present in the secondary waste use ethanol to convert short-chain into medium-chain carboxylic acids. The medium-chain carboxylic acids were separated from the secondary waste using in-situ extraction (liquid-liquid extraction). In previous studies, laboratory-scale bioreactors without a dispersing function were used. To optimise production and extraction of medium-chain carboxylic acids, the bioreactors were equipped with a device to disperse the extraction solvent in the secondary waste. By increasing the surface area between the phases, the ability to extract the medium-chain carboxylic acids was improved. The study aimed to evaluate the impact of this dispersing process. Production and extraction rates of static bioreactors without dispersing were compared to those of dynamic bioreactors with dispersing on a laboratory scale, using leachate from a composting plant as secondary waste. The results confirmed that dispersion has a positive effect on the process. Dispersing increased the reduction of the nutrient ethanol, the production of medium-chain carboxylic acids in the secondary waste and the extracted medium-chain carboxylic acids.
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Ramírez Tapias, Yuly A., Guillermo D. Rezzani, Juan F. Delgado, Mercedes A. Peltzer, and Andrés G. Salvay. "New Materials from the Integral Milk Kefir Grain Biomass and the Purified Kefiran: The Role of Glycerol Content on the Film’s Properties." Polymers 16, no. 22 (November 5, 2024): 3106. http://dx.doi.org/10.3390/polym16223106.
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Microbial exopolymers are gaining attention as sources for the development of biodegradable materials. Milk kefir, a fermented dairy product produced by a symbiotic community of microorganisms, generates milk kefir grains as a by-product, consisting of the polysaccharide kefiran and proteins. This study develops two materials, one from whole milk kefir grains and another from purified kefiran. Film-forming dispersions were subjected to ultrasonic homogenisation and thermal treatment, yielding homogeneous dispersions. Kefiran dispersion exhibited lower pseudoplastic behaviour and higher viscous consistency, with minimal effects from glycerol. Both films exhibited continuous and homogeneous microstructures, with kefiran films being transparent and milk kefir films displaying a yellowish tint. Analysis revealed that milk kefir films comprised approximately 30% proteins and 70% kefiran. Kefiran films demonstrated stronger interpolymeric interactions, as evidenced using thermogravimetric and mechanical tests. Glycerol increased hydration while decreasing thermal stability, glass transition temperature, elastic modulus, and tensile strength in both films. However, in kefiran films, elongation at the break and water vapour permeability decreased at low glycerol content, followed by an increase at higher plasticiser contents. This suggests an unusual interaction between glycerol and kefiran in the absence of proteins. These findings underscore differences between materials derived from the whole by-product and purified kefiran, offering insights into their potential applications.
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Vieira, Jessica, Marilu Chaves Gomes Dresch Camargo, Rafaela de Souza Marquezoni, Eloiza Cristina Martelli, Jessica Cassia Da Silva, Natália Arisa Nakamura Lima, and Rinaldo Ferreira Gandra. "Susceptibility of airborne fungi to the mycocins produced by <em>Wickerhamomyces anomalus</em>." Brazilian Journal of Health Review 5, no. 5 (September 27, 2022): 19824–29. http://dx.doi.org/10.34119/bjhrv5n5-162.
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Atmospheric air is the most used and most successful dispersion medium for fungi. Airborne fungi can establish themselves and contaminate the air, reducing the quality of life of the organisms that circulate there. The broad spectrum of antimicrobial activity and great stability led to the use of Wickerhamomyces anomalus as a biocontrol agent, since it could be classified as a low-risk microorganism, rarely traced in human samples. In addition, the antimicrobial action of mycocins produced from this yeast in eukaryotic and prokaryotic microorganisms is already proven. The aim of the present study was to evaluate the inhibition of airborne fungi by mycocins. The passive sedimentation technique was used in Petri dishes exposed in an external environment. The exposed plates consisted of a control group, consisting only of Sabouraud Dextrose Agar medium, and another test, composed of medium and supernatant of mycocins from Wickerhamomyces anomalus. The growth of 6 genera of fungi was observed on the control plates: Cladosporium spp., Penicillium spp., Alternaria spp. Aspergillus spp., Chrysosporium spp. and Fusarium spp. While, on the test plates, there was no growth of microorganisms. Therefore, we concluded that the mycocins produced by Wickerhamomyces anomalus were able to inhibit the growth of airborne fungi.
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CHIRINOS, Hugo David, and Sueli CARVALHO DE JESUS. "INFLUENCE OF THE VOLATILE FATTY ACID CONTENT TO RADIATION VULCANIZED NATURAL RUBBER LATEX (RVNRL)." Periódico Tchê Química 09, no. 17 (January 20, 2012): 38–41. http://dx.doi.org/10.52571/ptq.v9.n17.2011.28_periodico17_pgs_28_37.pdf.
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Natural rubber latex is a dispersion of natural rubber particles in water. These particles are coated with a protein layer which will stabilize the dispersion in water by forming an electric charge in the layer. Any different condition affecting this layer disturbs the stability of dispersion. Microorganism attack disturbs the protein layer and consequently the stability of the dispersion. By adding 1.2% by weight of NH3, the stability of the dispersion can be improved. The fresh latex was irradiated by Co-60 with irradiation dose of 10, 20, 30, 40 and 100 kGy. The results showed a relationship between the volatile fatty acid content (VFA, product from microorganism attack on carbohydrate) and the green strength or the physical properties of vulcanized film. Low VFA number showing a higher physical strength of the film either un-vulcanized or vulcanized. It appeared that the structure was responsible in yielding a good physical property of the film.
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Lenchenko, E. M., N. P. Sachivkina, D. A. Blumenkrants, and A. Yu Arsenyuk. "Visualization of microbial biofilms in case of digestive disorders in lambs." Veterinary Science Today 1, no. 1 (March 29, 2021): 59–67. http://dx.doi.org/10.29326/2304-196x-2021-1-36-59-67.
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The paper demonstrates morphometric and densitometric parameters of microbial biofilms recovered from lambs with digestive disorders. Changes of quantitative and species composition of the intestinal microbiocenoses in the lambs with digestive disorders were compared with the ones of the clinically healthy lambs. Light microscopy results demonstrated formation of three-dimensional biofilm structure in the form of dense grid consisting of gram-negative and gram-positive bacteria, yeast cells, hyphas and pseudohyphas surrounded with intracellular polymer matrix. Presence of blastospores aided to the increased number of cells attached to the substrate, and biofilm was formed, which consisted of rod and round cells attached to the microfungi cells. In the process of dispersion that occurred during the destruction of the intercellular matrix and bacterial and yeast cell detachment, branched structures separated from the microcolonies and colonized microorganism- free regions of the substrate. The intensity of biofilm formation by the microorganisms under study was evaluated by optic density measurement in 48 hours of cultivation. Fluorescence microscopy results demonstrated that the dynamics of changes of the viable microbial structures was specified by intermittent periods of increased or decreased biofilm formation intensity. Cells characterized by active growth and replication and forming alternating subpopulations were detected in the examined microbial cultures. When determining the viability of the microorganisms in the biofilms, the viable (green fluorescence) and non-viable (red fluorescence) cells were differentiated.
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Malek, Fadila. "Microorganism Carrier-Surface Method as an Efficient Model for Microscopic Characterization of Biofilm Structure and Dispersion in Dairy Associated Spore-Forming Bacteria." Journal of Food Engineering and Technology 12, no. 1 (May 25, 2023): 21–28. http://dx.doi.org/10.32732/jfet.2023.12.1.21.
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Dispersion, defined as the release of planktonic cells is the final stage of biofilm development and of major significance in clinical and industrial settings. Currently, biofilm dispersion is considered as a promising avenue for biofilm control and an important topic research. However, a problem facing such research projects is how to induce planktonic life in a biofilm. Numerous systems are used for the investigation of biofilm dispersion, including dynamic continuous or static batch systems. This mini-review describes the usefulness of the microorganism carrier-surface method as a simple biofilm growth model which successfully allowed microscopic characterization of biofilm structure and dispersion in dairy-associated spore-forming bacteria and should be an efficient model for studying dispersion process.
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Kovalenko, Olexandra, Yaroslav Kizim, and Natalia Voroshylova. "EXTRACELLULAR POLYMERIC SUBSTANCE OF BIOFILMS IN THE FORMATION OF ANTIMICROBIAL RESISTANCE OF MICROORGANISMS." Ukrainian Scientific Medical Youth Journal, no. 2(110) (June 27, 2019): 6–12. http://dx.doi.org/10.32345/usmyj.2(110).2019.6-12.
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Abstract. The analysis of modern literature data on the mechanisms of the formation of antibiotic resistance and the role of extracellular polymeric substance in biofilms, which are the main form of microbial existence. The role of extracellular polymeric substance in limiting of the effect of unfavorable factors as well as the regularity and necessity of its formation for the community of microorganisms were discussed. The position on the permanent character of phenotype dispersion of microorganisms is postulated. This dispersion doesn’t provide the formation of more resistant strains only, but plays the prominent role in the permanent formation of various forms, that aren’t viable under given conditions but play the role of a depot of building material for extracellular polymeric substance. The mass death of low-resistant forms caused by the action of the antibiotic ensures saturation of the extracellular polymeric substance by dechromatized DNA, that increases the resistance of the microbial socium and contributes to the further formation of multiresistance.
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Hopkins, D. W., S. J. Macnaughton, and A. G. O'Donnell. "A dispersion and differential centrifugation technique for representatively sampling microorganisms from soil." Soil Biology and Biochemistry 23, no. 3 (January 1991): 217–25. http://dx.doi.org/10.1016/0038-0717(91)90055-o.
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Hopkins, D. W., A. G. O'Donnell, and S. J. Macnaughton. "Evaluation of a dispersion and elutriation technique for sampling microorganisms from soil." Soil Biology and Biochemistry 23, no. 3 (January 1991): 227–32. http://dx.doi.org/10.1016/0038-0717(91)90056-p.
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VISILEANU, EMILIA, ALEXANDRA ENE, CARMEN MIHAI, and ALINA VLADU. "Textile structures for the treatment of burn wounds – characterization of elastic and antibacterial properties." Industria Textila 74, no. 02 (May 2, 2023): 246–55. http://dx.doi.org/10.35530/it.074.02.2022108.
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The paper shows the elastic and antibacterial features of the textile structures (Layer I and III) which make up a three-layer composite material with well-defined features, aimed at the treatment of human burns. The textile structures obtained through weaving (5 variants) and interweaving (3 variants) were further treated with active substances: collagen, colloidal silver, CMC, clay, hyaluronic acid, polyurethane, etc. By using specialized software, fundamental statistical indicators were calculated for the modulus of elasticity and anisotropy variables: mean, dispersion and standard deviation, median and quartiles, skewness, and kurtosis for asymmetry and highlighting the cases in which interventions should be carried out. The histograms and box-plot graphs of the modulus of elasticity and anisotropy variables were obtained. For the functionalized textile structures, with different levels of anisotropy, the antibacterial activity was evaluated on Gram-positive microorganisms (Staphylococcus aureus ATCC 6538) and Gram-negative (Escherichia coli ATCC 8739) and Candida albicans, variety ATCC 10231 by determining the logarithmic and percentage reduction of microorganism populations. The hemocompatibility was determined by evaluating the hemolytic index (ASTM F756-13). The results obtained led to the definition of the combinations of structures of the multilayer matrix.
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Carotenuto, Federico, Teodoro Georgiadis, Beniamino Gioli, Christel Leyronas, Cindy E. Morris, Marianna Nardino, Georg Wohlfahrt, and Franco Miglietta. "Measurements and modeling of surface–atmosphere exchange of microorganisms in Mediterranean grassland." Atmospheric Chemistry and Physics 17, no. 24 (December 18, 2017): 14919–36. http://dx.doi.org/10.5194/acp-17-14919-2017.
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Abstract. Microbial aerosols (mainly composed of bacterial and fungal cells) may constitute up to 74 % of the total aerosol volume. These biological aerosols are not only relevant to the dispersion of pathogens, but they also have geochemical implications. Some bacteria and fungi may, in fact, serve as cloud condensation or ice nuclei, potentially affecting cloud formation and precipitation and are active at higher temperatures compared to their inorganic counterparts. Simulations of the impact of microbial aerosols on climate are still hindered by the lack of information regarding their emissions from ground sources. This present work tackles this knowledge gap by (i) applying a rigorous micrometeorological approach to the estimation of microbial net fluxes above a Mediterranean grassland and (ii) developing a deterministic model (the PLAnET model) to estimate these emissions on the basis of a few meteorological parameters that are easy to obtain. The grassland is characterized by an abundance of positive net microbial fluxes and the model proves to be a promising tool capable of capturing the day-to-day variability in microbial fluxes with a relatively small bias and sufficient accuracy. PLAnET is still in its infancy and will benefit from future campaigns extending the available training dataset as well as the inclusion of ever more complex and critical phenomena triggering the emission of microbial aerosol (such as rainfall). The model itself is also adaptable as an emission module for dispersion and chemical transport models, allowing further exploration of the impact of land-cover-driven microbial aerosols on the atmosphere and climate.
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Frolov, Georgy A., Yakov N. Karasenkov, Alexander A. Gusev, Olga V. Zakharova, Anna Yu Godymchuk, Denis V. Kuznetsov, and Valerii K. Leont'ev. "Antimicrobial Activity of Differently Concentrated Nanoparticle Dispersions." Nano Hybrids and Composites 13 (January 2017): 239–47. http://dx.doi.org/10.4028/www.scientific.net/nhc.13.239.
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Preparation of nontoxic antimicrobial solutions is a priority in the development of new antibiotics. The in vitro effect of the chemical composition of the dispersed phase and dissolved solids in the dispersion medium on the antimicrobial properties of aqueous colloidal solutions of nanoparticles of a number of metals and metal oxides against microorganisms of different species - bacterial dental plaque, Bacillus cereus, and spores of vaccine strain Bacillus anthracis STI - 1 were studied in this work.
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Ferris, F. G., W. S. Fyfe, T. Witten, S. Schultze, and T. J. Beveridge. "Effect of mineral substrate hardness on the population density of epilithic microorganisms in two Ontario rivers." Canadian Journal of Microbiology 35, no. 7 (July 1, 1989): 744–47. http://dx.doi.org/10.1139/m89-122.
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Adherent epilithic microorganisms recovered from rocks submerged 10 to 20 cm in two different rivers were examined by electron microscopy and enumerated after dispersion in M-9 salts by viable plate counts. Bacterial cells concentrated in microcolonies were often observed attached to the surface of algae, cyanobacteria, and organic detritus. This structured communal mode of growth was common among epilithic microbial communities of different rock types. However, counts of heterotrophic bacteria from limestone (106 to 107 cfu/cm2) were 10- to 100-fold greater than corresponding values from granite, gabbro, rhyolite, basalt, and quartz. Cyanobacteria and algae were an order of magnitude less abundant compared with their bacterial counterparts. These variations in population densities of epilithic microorganisms present on different rocks were inversely related to mineral substrate hardness.Key words: epilithic microorganisms, mineral hardness.
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Zheng, Yan Mei, Dong Xia, Yuan Peng Wang, and Dao Hua Sun. "Simulation of Removal of MTBE in Groundwater by Biosparging." Applied Mechanics and Materials 556-562 (May 2014): 4085–88. http://dx.doi.org/10.4028/www.scientific.net/amm.556-562.4085.
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Biosparging is one of the effective in situ-technology to removal the organic contaminants. The experiments of removing MTBE by biosparging were carried out in a soil column. the results showed that there were the tailing of contaminants in the column without microorganism according with the microorganism. The removal of organic contaminants by biosparging was simulated by a mathematical model, which considered the advective flux, diffusion, mechanical dispersion, interphase mass transfer and biodegrade. The simulation results agreed with the experimental results well.
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Perales Pérez, Oscar, and Yarilyn CedeñoMattei. "SYNTHESIS, CHARACTERIZATION, AND ASSESSMENT OF THE ANTIMICROBIAL ACTIVITY OF MGO – CALCIUM ALGINATE POROUS BEADS." Revista Cientifica TECNIA 26, no. 2 (March 1, 2017): 7. http://dx.doi.org/10.21754/tecnia.v26i2.52.
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La dispersión de nanopartículas antibacterianas en matrices poliméricas biocompatibles, no tóxicas y biodegradables permitirá el desarrollo de materiales más eficientes y efectivos para la conservación de alimentos, la eliminación de contaminantes y la protección contra microorganismos que comprometen la salud humana. Los materiales bactericidas nanométricos tienen una relación superficie / volumen muy grande que les permite interactuar con más copias de moléculas biológicas, y por lo tanto, mejorar la eficacia antimicrobiana. Más recientemente, se ha sugerido la actividad antimicrobiana del MgO amigable con el medio ambiente y químicamente estable. La incorporación de compuestos bactericidas en una matriz polimérica puede combinar la estabilidad física proporcionada por la matriz polimérica con las propiedades antimicrobianas de los agentes antimicrobianos dispersados como partıculas pequeñas sólidas. Sobre esta base, la presente investigación se centrará en el desarrollo de mezclas de partículas inorgánicas poliméricas biocompatibles, los denominados nanocompuestos, con actividad antimicrobiana sintonizable y mejorada. Se confirmó la actividad antimicrobiana de perlas de alginato cálcico - MgO (que oscilaban entre 0% y 40% p / p MgO) contra E. coli. Las perlas que contenían 20% p / p de MgO inhibían completamente el crecimiento bacterial de la E. coli. Palabras clave.-Alginato de calcio, Cuentas porosas, Óxido de magnesio, Actividad antimicrobiana. ABSTRACTThe dispersion of antibacterial nanoparticles into bio-compatible, non-toxic and bio-degradable polymeric matrices will enable the development of more efficient and effective materials for food preservation, removal of contaminants, and protection against human health-compromising microorganisms. Nanometric bactericidal materials have a very large surface to volume ratio that enable them to attach more copies of biological molecules, and hence, enhance antimicrobial efficiency. More recently, the antimicrobial activity of environmental-friendly and chemically stable MgO has been suggested. The incorporation of bactericidal compounds into a polymeric matrix can combine physical stability provided by the polymeric matrix with the antimicrobial properties of antimicrobial agents dispersed as solid tiny particles. On this basis, the present research will be focused on the development of biocompatible polymer-inorganic particle mixtures, so-called nanocomposites, with tunable and enhanced antimicrobial activity. The antimicrobial activity of calcium alginate – MgO beads (ranging from 0% - 40% w/w MgO) against E. coli was confirmed. Beads containing 20% w/w of MgO fully inhibited the E. coli. bacterial growth.. Keywords.- Calcium alginate, Porous beads, Magnesium oxide, Antimicrobial activity.
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Artyukh, T. V., T. N. Sokolova, and V. M. Sheibak. "MODERN METHODS FOR RESEARCHING MICROBIAL BIOFILMS OF THE ENTEROBACTERIACEAE FAMILY." Hepatology and Gastroenterology 5, no. 1 (June 10, 2021): 30–36. http://dx.doi.org/10.25298/2616-5546-2021-5-1-30-36.
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The article outlines the main methods of studying microbial biofilms, which make it possible to reveal: the patterns of biofilm formation by microorganisms of the Enterobacteriaceae family, genetic programs regulating the processes of film formation, qualitative and quantitative characteristics of the components of microbial communities, the influence of external factors on the stages of biofilm formation and dispersion. The study of the phenomenon of film formation in combination with monitoring the resistance of intestinal microorganisms in the biofilm to antibacterial drugs will make it possible to get closer to understanding the role of biofilms in the course of infectious processes of a microbial origin.
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Wojciechowski, Kamil, Małgorzata Gutarowicz, Kamil Janke, Ilona Jurek, Marcin Kaczorowski, Jolanta Mierzejewska, and Paweł Parzuchowski. "Colloidal Stability of Positively Charged Dispersions of Styrene and Acrylic Copolymers in the Presence of TiO2 and CaCO3." Colloids and Interfaces 3, no. 1 (January 30, 2019): 20. http://dx.doi.org/10.3390/colloids3010020.
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Increasing antibiotic resistance of several pathogenic microorganisms calls for alternative approaches to prevent spreading of bacterial diseases. We propose to employ for this purpose coatings obtained from positively charged latex dispersions. In this contribution we characterize aqueous mixed dispersions containing TiO2 or CaCO3 and methyl methacrylate-ethyl acrylate or styrene-ethyl acrylate copolymers synthesized using a cationic surfactant, cetyltrimethylammonium bromide as an emulsifier. Particle size, electrokinetic (ζ) potential of the mixed dispersions and the resulting thin films, as well as antimicrobial properties of the latter are described. The TiO2 and CaCO3 dispersions were stabilised with polyethyleneimine (PEI) and optimum pH for the mixed dispersions were chosen on the basis of ζ-potential measurements. For TiO2, the maximum ζ = +35 mV was found at pH 7.5, and for CaCO3, pH was set at 8.2 (ζ = +38 mV), to prevent its dissolution. In most 1:1 mixtures of TiO2 or CaCO3 with the cetyltrimethylammonium bromide (CTAB)-stabilised latex dispersions, two distinct particles populations were observed, corresponding to the bare latex and bare TiO2 or CaCO3 fractions. Films made of the mixed dispersions remained positively charged and showed antimicrobial activity similar or reduced with respect to the bare polymer films.
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Dehkharghani, Amin, Nicolas Waisbord, Jörn Dunkel, and Jeffrey S. Guasto. "Bacterial scattering in microfluidic crystal flows reveals giant active Taylor–Aris dispersion." Proceedings of the National Academy of Sciences 116, no. 23 (May 16, 2019): 11119–24. http://dx.doi.org/10.1073/pnas.1819613116.
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The natural habitats of planktonic and swimming microorganisms, from algae in the oceans to bacteria living in soil or intestines, are characterized by highly heterogeneous fluid flows. The complex interplay of flow-field topology, self-propulsion, and porous microstructure is essential to a wide range of biophysical and ecological processes, including marine oxygen production, remineralization of organic matter, and biofilm formation. Although much progress has been made in the understanding of microbial hydrodynamics and surface interactions over the last decade, the dispersion of active suspensions in complex flow environments still poses unsolved fundamental questions that preclude predictive models for microbial transport and spreading under realistic conditions. Here, we combine experiments and simulations to identify the key physical mechanisms and scaling laws governing the dispersal of swimming bacteria in idealized porous media flows. By tracing the scattering dynamics of swimming bacteria in microfluidic crystal lattices, we show that hydrodynamic gradients hinder transverse bacterial dispersion, thereby enhancing stream-wise dispersion ∼100-fold beyond canonical Taylor–Aris dispersion of passive Brownian particles. Our analysis further reveals that hydrodynamic cell reorientation and Lagrangian flow structure induce filamentous density patterns that depend upon the incident angle of the flow and disorder of the medium, in striking analogy to classical light-scattering experiments.
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Li, Shangjian, Jiajia Chen, Yuntong Liu, Honghao Qiu, Wei Gao, Kundian Che, Baogang Zhou, Ran Liu, and Wenzhong Hu. "Preparation of Citral Oleogel and Antimicrobial Properties." Gels 9, no. 12 (November 25, 2023): 930. http://dx.doi.org/10.3390/gels9120930.
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The objective of this study was to analyze a natural and safe oleogel with antimicrobial properties that can replace animal fats while lengthening the product’s shelf life. The oleogel was created using direct dispersion (MG-SO), and its material characterization exhibited the exceptional performance of the hybrid gelant. Additionally, citral was integrated into the oil gel to prepare the citral oleogel (MG-SO). The antimicrobial nature of the material was examined and the findings revealed that it inhibited the growth of various experimental model bacteria, including Escherichia coli, Staphylococcus aureus, Aspergillus niger, Botrytis cinerea, and Rhizopus stolonifer. In addition, the material had a comparable inhibitory impact on airborne microorganisms. Lastly, MG-SON was utilized in plant-based meat patties and demonstrated an ability to significantly reduce the growth rate of microorganisms.
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Truskewycz, Adam, Taylor D. Gundry, Leadin S. Khudur, Adam Kolobaric, Mohamed Taha, Arturo Aburto-Medina, Andrew S. Ball, and Esmaeil Shahsavari. "Petroleum Hydrocarbon Contamination in Terrestrial Ecosystems—Fate and Microbial Responses." Molecules 24, no. 18 (September 19, 2019): 3400. http://dx.doi.org/10.3390/molecules24183400.
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Petroleum hydrocarbons represent the most frequent environmental contaminant. The introduction of petroleum hydrocarbons into a pristine environment immediately changes the nature of that environment, resulting in reduced ecosystem functionality. Natural attenuation represents the single, most important biological process which removes petroleum hydrocarbons from the environment. It is a process where microorganisms present at the site degrade the organic contaminants without the input of external bioremediation enhancers (i.e., electron donors, electron acceptors, other microorganisms or nutrients). So successful is this natural attenuation process that in environmental biotechnology, bioremediation has developed steadily over the past 50 years based on this natural biodegradation process. Bioremediation is recognized as the most environmentally friendly remediation approach for the removal of petroleum hydrocarbons from an environment as it does not require intensive chemical, mechanical, and costly interventions. However, it is under-utilized as a commercial remediation strategy due to incomplete hydrocarbon catabolism and lengthy remediation times when compared with rival technologies. This review aims to describe the fate of petroleum hydrocarbons in the environment and discuss their interactions with abiotic and biotic components of the environment under both aerobic and anaerobic conditions. Furthermore, the mechanisms for dealing with petroleum hydrocarbon contamination in the environment will be examined. When petroleum hydrocarbons contaminate land, they start to interact with its surrounding, including physical (dispersion), physiochemical (evaporation, dissolution, sorption), chemical (photo-oxidation, auto-oxidation), and biological (plant and microbial catabolism of hydrocarbons) interactions. As microorganism (including bacteria and fungi) play an important role in the degradation of petroleum hydrocarbons, investigations into the microbial communities within contaminated soils is essential for any bioremediation project. This review highlights the fate of petroleum hydrocarbons in tertial environments, as well as the contributions of different microbial consortia for optimum petroleum hydrocarbon bioremediation potential. The impact of high-throughput metagenomic sequencing in determining the underlying degradation mechanisms is also discussed. This knowledge will aid the development of more efficient, cost-effective commercial bioremediation technologies.
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Lakshmi, S. K. Prasanna, S. Sreedhar, and S. V. V. Rama Devi. "Numerical Investigation of Magnetohydrodynamic Flow of Reiner– Philippoff Nanofluid with Gyrotactic Microorganism Using Porous Medium." Engineering World 5 (July 11, 2023): 57–74. http://dx.doi.org/10.37394/232025.2023.5.8.
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Nanoparticles facilitate the enrichment of heat transmission, which is crucial in many industrial and technical phenomena. The suspension of nanoparticles with microbes is another intriguing study area that is pertinent to biotechnology, health sciences, and medicinal applications. In the dispersion of nanoparticles, the conventional non-Newtonian fluid Reiner-Philippoff flows across a stretching sheet, which is examined in this article using numerical analysis. This study investigates the numerical investigation of Arrhenius reaction, heat radiation, and vicious variation variations on a Reiner-Philippoff nanofluid of MHD flow through a stretched sheet. Thus, for the current nanofluid, nanoparticles and bio-convection are highly crucial. The set of nonlinear differential equations is translated into Ordinary Differential Equations (ODEs) utilizing the requisite translation of similarities. These collected simple ODE are solved using the MATLAB computational tool bvp4c method. The graphical results for the velocity, concentration, motile microorganisms, and temperature profile are defined using the thermophoresis parameter and the Brownian motion respectively. Consider a tube containing gyrotactic microbes and a regular flow of nanofluid which is electrically conducted through a porous stretched sheet surface. This nonlinear differential problem is solved by a hybrid numerical solution method using fourth-order Runge-Kutta with shooting technique. The optimization method also performs well in terms of predicting outcomes accurately. As a result, the research applies the Bayesian Regularization Method (BRM) to improve the accuracy of the prediction results. Physical constraints are plotted against temperature, velocity, concentration, and microorganism profile trends and they are briefly described.
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Immich, Gabriel, Caroline Visentin, Adeli Beatriz Braun, Cleomar Reginatto, and Antônio Thomé. "Earthworm-assisted bioremediation in a clayey soil contaminated by biodiesel." Caderno Pedagógico 20, no. 6 (November 29, 2023): 1710–29. http://dx.doi.org/10.54033/cadpedv20n6-004.
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The Success in bioremediation techniques depends on factors such as site characteristics, environmental factors, contaminant nature (temperature, pH, nutrients), presence of suitable biodegradable genes, the contamination nature, etc. Earthworms can aid in these on these factors, through their biological, chemical and physical characteristics, they aerate the soil, improve the nutritional status and help to release the contaminants binding in the soil particles, besides, they help the degrading microorganisms’ dispersion. Biodiesel is a contaminant widely used in the fuel industry, and its production is encouraged. Thus, the aim of this study is analyzed the efficiency of an earthworm species (Eudrilus eugeniae) to remediated a residual clayey soil contaminated with biodiesel, with and without assistance for biostimulated native microorganisms. Therefore, a clay soil was contaminated with biodiesel (24 g / kg) and the ability of the earthworms of the species (Eudrilus eugeniae) to degrade biodiesel with or without biostimulation (cattle manure) for a period of 90 days was analyzed. Earthworms and cow dung have proved to be efficient for remediation processes, providing 100% degradation at the end of 90 days for "biostimulation and earthworm" and "biostimulation, microorganisms and earthworm" samples. Thus, the use of earthworms contributes to a faster remediation process and, together with microorganisms, they are a more sustainable solution for application in areas contaminated with fuels.
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Saleemi, Mansab Ali, Mohammad Hosseini Fouladi, Phelim Voon Chen Yong, and Eng Hwa Wong. "Elucidation of Antimicrobial Activity of Non-Covalently Dispersed Carbon Nanotubes." Materials 13, no. 7 (April 3, 2020): 1676. http://dx.doi.org/10.3390/ma13071676.
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Microorganisms have begun to develop resistance because of inappropriate and extensive use of antibiotics in the hospital setting. Therefore, it seems to be necessary to find a way to tackle these pathogens by developing new and effective antimicrobial agents. Carbon nanotubes (CNTs) have attracted growing attention because of their remarkable mechanical strength, electrical properties, and chemical and thermal stability for their potential applications in the field of biomedical as therapeutic and diagnostic nanotools. However, the impact of carbon nanotubes on microbial growth has not been fully investigated. The primary purpose of this research study is to investigate the antimicrobial activity of CNTs, particularly double-walled and multi-walled nanotubes on representative pathogenic strains such as Gram-positive bacteria Staphylococcus aureus, Gram-negative bacteria Pseudomonas aeruginosa, Klebsiella pneumoniae, and fungal strain Candida albicans. The dispersion ability of CNT types (double-walled and multi-walled) treated with a surfactant such as sodium dodecyl-benzenesulfonate (SDBS) and their impact on the microbial growth inhibition were also examined. A stock concentration 0.2 mg/mL of both double-walled and multi-walled CNTs was prepared homogenized by dispersing in surfactant solution by using probe sonication. UV-vis absorbance, Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM) were used for the characterization of CNTs dispersed in the surfactant solution to study the interaction between molecules of surfactant and CNTs. Later, scanning electron microscopy (SEM) was used to investigate how CNTs interact with the microbial cells. The antimicrobial activity was determined by analyzing optical density growth curves and viable cell count. This study revealed that microbial growth inhibited by non-covalently dispersed CNTs was both depend on the concentration and treatment time. In conclusion, the binding of surfactant molecules to the surface of CNTs increases its ability to disperse in aqueous solution. Non-covalent method of CNTs dispersion preserved their structure and increased microbial growth inhibition as a result. Multi-walled CNTs exhibited higher antimicrobial activity compared to double-walled CNTs against selected pathogens.
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Go, Eun Ji, Byeong Ryeol Ryu, Gyeong Ju Gim, Ha Yeon Lee, Han Sol You, Hyun Bok Kim, Hyun Tai Lee, et al. "Hot-Melt Extrusion Enhances Antioxidant Effects of Mulberry on Probiotics and Pathogenic Microorganisms." Antioxidants 11, no. 11 (November 21, 2022): 2301. http://dx.doi.org/10.3390/antiox11112301.
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Mulberry is a rich source of anthocyanins (ACNs) known to possess biological activities. However, these ACNs are unstable in high pH, heat, and aqueous environments with a low bioavailability. In this study, a colloidal dispersion was prepared by hot melt extrusion with proper excipients. In this process, a hydrophilic polymer matrix was used to confirm the stability of the compound in high pH, high temperature, and aqueous media. It was confirmed that the particle size and the polydispersity index value were reduced, thereby improving the solubility. In vitro release studies revealed that the extrudate had a sustained release compared to a non-extruded product. As a result of measuring changes of intestinal microorganisms (Lacticaseibacillus rhamnosus, Pediococcus pentosaceus, Escherichia coli, Enterococcus faecalis, and Staphylococcus aureus), contents of probiotics were found to be increased whereas contents of pathogenic microorganisms were decreased. Thus, hot-melt extrusion could enhance the stability of ACN with prolonged release. The processed formulation exhibited probiotic properties and antimicrobial activities against pathogenic intestinal microflora.
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Kandukuri, Naga Hari Krishna, Kishore Babu M, Bhargavi M, Pranay K, Swetha K, Rajeswari K, Gayatri M, and Jaya Sri K. "Invitro antimicrobial activity of bitter melon leaf extract using well diffusion method." Journal of Modern Techniques in Biology and Allied Sciences 1, no. 1 (September 30, 2024): 13–19. https://doi.org/10.70604/jmtbas.v1i1.10.
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The aim of present study examines the invitro antimicrobial properties of leaf removes from Momordica charantia, commonly known as bitter melon. Utilizing different extraction techniques, we arranged separates and considered their viability in contrast to a scope of pathogenic microorganisms, including microbes and growths. Using a paper plate dispersion test, its antimicrobial viability against Staphylococcus aureus, Salmonella typhi, methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli, and Pseudomonas aeruginosa was assessed using its methanolic extracts. The Agar Well-Dispersion Strategy ensured adequate antifungal efficacy against specific strains of Penicillium and Aspergillus. The base inhibitory focus (MIC) was determined using the Stock Weakening method and the Agar Well-Dispersion method. Antimicrobial examines, including agar dissemination and least inhibitory fixation (MIC) tests, were directed to decide the viability of the concentrates. The outcomes exhibited huge antimicrobial properties, with fluctuating levels of hindrance across various microbial strains. These discoveries propose that Momordicacharantia leaf separates have likely remedial applications as normal antimicrobial specialists, featuring the requirement for additional investigation into their dynamic mixtures and instruments of activity. This study contributes to the growing interest in plant-derived substances for combating microbial resistance.
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Kudrinskiy, Alexey, Pavel Zherebin, Alexander Gusev, Olga Shapoval, Jaeho Pyee, Georgy Lisichkin, and Yurii Krutyakov. "New Relevant Descriptor of Linear QNAR Models for Toxicity Assessment of Silver Nanoparticles." Nanomaterials 10, no. 8 (July 25, 2020): 1459. http://dx.doi.org/10.3390/nano10081459.
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The use of silver nanoparticles (NPs) in medical, industrial and agricultural fields is becoming more widespread every year. This leads to an increasing number of experimental toxicological and microbiological studies of silver NPs aimed at establishing the risk–benefit ratio for their application. The following key parameters affecting the biological activity of silver dispersions are traditionally taken into consideration: mean diameter of NPs, surface potential of NPs and equilibrium concentration of Ag+. These characteristics are mainly predetermined by the chemical nature of the capping agent used for stabilization. However, the extent to which they influence the biological activity and the toxicity of silver NPs varies greatly. In this work, dispersions of silver NPs stabilized with a wide array of substances of different chemical nature were used for quantitative evaluation of whether the various measurable properties of silver NPs fit as descriptors of linear QNAR (quantitative nanostructure–activity relationship) models for silver NP toxicity evaluation with respect to a model eukaryotic microorganism—Saccharomyces cerevisiae yeast cells. It was shown that among the factors that determine silver NP toxicity, the charge of particles, their colloidal stability and the ability to generate Ag+ ions carry more importance than the descriptors related to the particle size. A significant synergistic effect between the ζ-potential and the colloidal stability of silver NPs on their toxicity was also discovered. Following this, a new descriptor has been proposed for the integral characterization of the silver dispersion colloidal stability. According to the obtained data, it can be considered applicable for building QNAR models of higher efficacy. The validity testing of the proposed model for theoretical prediction of silver NP toxicity using a wide range of living organisms has shown that this new descriptor correlates with toxicity much better compared to most traditionally used descriptors. Consequently, it seems promising in terms of being used not only in situations involving the rather narrow array of the objects tested, but also for the construction of silver NP toxicity models with respect to other living organisms.
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Haas, Charles N. "Microbial Sampling: Is It Better to Sample Many Times or Use Large Samples?" Water Science and Technology 27, no. 3-4 (February 1, 1993): 19–25. http://dx.doi.org/10.2166/wst.1993.0314.
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Repeated sampling of a water (raw, Ssished, recreational) is often used to assess microbial quality. Microbial distributions have often been found to be negative binomial distributed in such repeated samples. Under these conditions, it is shown that it is better to use a large number of small volume samples than vice versa, providing that the negative binomial dispersion parameter remains unaffected by volume. Further research is needed to determine if the latter assumption, which influences the conclusion proposed, is valid for various classes of microorganisms in various types of waters.
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Islam Siddique, Md Nurul, B. K. Zaied, Noraaini Haji Ali, Mohd Zamri Bin Ibrahim, and Shahrul Bin Ismail. "The Use of Carbon based Materials for Improving Methane Production from Ethanol Anaerobic Fermentation: Viability Analysis and Fertilizer Recovery." Asian Journal of Chemistry 34, no. 7 (2022): 1848–56. http://dx.doi.org/10.14233/ajchem.2022.23805.
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The impacts of carbon-based sources on anaerobic digestion methane generation were investigated in this study. The study revealed that bio-solids and hydrochars may increase accumulative methane output by 16% to 30%. Nevertheless, there is no significant difference (statistically) (p > 0.05) in methane production from hydrochars and biosolids generated at, unlike temperatures. Biosolids and hydrochars augmented microorganisms that may contribute indirect interspecies electron transfer. Microorganisms’ direct interspecies electron transfer (DIET) in a stable environment created by carbon-based compounds with homogeneous dispersion and electrons were transported via an aromatic functional group on the surface of the material. From the fermented effluent, sludge recapture was 0.09 m3 sludge/m3 wastewater. The time required to recoup investment was calculated to be 3.72 years. This study suggested that the impact of surface characteristics of carbon-based sources on methane generation in anaerobic fermentation and proposes a novel method for reusing discarded tea grounds.
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Venditto, Immacolata, Helena Santos, Luís M. A. Ferreira, Kazuo Sakka, Carlos M. G. A. Fontes, and Shabir Najmudin. "Overproduction, purification, crystallization and preliminary X-ray characterization of the family 46 carbohydrate-binding module (CBM46) of endo-β-1,4-glucanase B (CelB) fromBacillus halodurans." Acta Crystallographica Section F Structural Biology Communications 70, no. 6 (May 10, 2014): 754–57. http://dx.doi.org/10.1107/s2053230x14008395.
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Plant cell-wall polysaccharides offer an abundant energy source utilized by many microorganisms, thus playing a central role in carbon recycling. Aerobic microorganisms secrete carbohydrate-active enzymes (CAZymes) that catabolize this composite structure, comprising cellulose, hemicellulose and lignin, into simple compounds such as glucose. Carbohydrate-binding modules (CBMs) enhance the efficacy of associated CAZYmes. They are organized into families based on primary-sequence homology. CBM family 46 contains more than 40 different members, but has yet to be fully characterized. Here, a recombinant derivative of the C-terminal family 46 CBM module (BhCBM46) ofBacillus haloduransendo-β-1,4-glucanase B (CelB) was overexpressed inEscherichia coliand purified by immobilized metal-ion affinity chromatography. Preliminary structural characterization was carried out onBhCBM46 crystallized in different conditions. The crystals ofBhCBM46 belonged to the tetragonal space groupI4122. Data were collected for the native form and a selenomethionine derivative to 2.46 and 2.3 Å resolution, respectively. TheBhCBM46 structure was determined by a single-wavelength anomalous dispersion experiment usingAutoSolfrom thePHENIXsuite.
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Mironov, V. V., E. S. Trofimchuk, V. V. Ostrikova, A. V. Plutalova, M. A. Moskvina, A. A. Shchelushkina, E. V. Chernikova, and D. S. Sokolova. "Polylactide Degradation in the Presence of Members of the Genus <i>Bacillus</i>." Микробиология 92, no. 5 (September 1, 2023): 527–32. http://dx.doi.org/10.31857/s0026365623600207.
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Abstract—Microorganisms of the genus Bacillus were shown to have different effects on the degradation of polylactide packaging material. The degradation experiment was carried out on an agar medium at a temperature of 55°C and pH 5.9 for 14 days. This is the first report on the abiotic hydrolysis significantly slowing down during incubation with B. licheniformis S8 and occurring in parallel with the main process, enzymatic hydrolysis. The latter involved sequential cleavage of monomer units from the end of the macromolecule and the formation of low molecular weight products used by microorganisms as a substrate; it contributed to a decrease in the mass of polylactide by 5.1%, while maintaining its molecular weight and decreasing the dispersion of molecular weights. In the presence of bacteria B. amyloliquefaciens, B. subtilis subsp. spizizenii, and B. subtilis subsp. inaquosorum, the polymer weight did not decrease, but the molecular weight decreased significantly, similar to abiotic hydrolysis.
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Corrales Ramírez, Lucía Constanza, Ligia Consuelo Sánchez Leal, and Melco Esteban Quimbayo Salamanca. "Microorganismos potencialmente fitopatógenos en aguas de riego proveniente de la cuenca media del rio Bogotá." Nova 16, no. 29 (September 10, 2018): 71–89. http://dx.doi.org/10.22490/24629448.2691.
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Objetivo. Identificar microorganismos fitopatógenos presentes en las aguas utilizadas para riego en la cuenca media del rio Bogotá. Métodos. Las muestras fueron tomadas en doce fincas de la cuenca media y analizadas con la técnica de filtración por membrana. Las bacterias se identificaron por bioquímica y los hongos por claves dicotomas. Resultados. El agua de riego analizada contenía bacterias como: E.coli, P. vulgaris, A. urinae, E. cloacae, B.cereus, S. marcescens, B. brevis, y en cuanto a los hongos se encontraron: Aspergillus fumigatus, Aspergillus flavus., Mucor sp., Rhizopus sp., Penicillium sp. y Fusarium sp. La presencia de estos potenciales fitopatógenos en el agua indican un alto riesgo de contaminación y dispersión de éstos en los cultivos.
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Lopes, Thiara Reis, Fernando Periotto, and Adelmo Lowe Pletsch. "Bacterial resistance in sanitary sewage sludge in different treatment systems." Management of Environmental Quality: An International Journal 28, no. 1 (January 9, 2017): 32–42. http://dx.doi.org/10.1108/meq-07-2015-0146.
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Purpose The purpose of this paper is to assess the occurrence and risk of dispersion in the environment of antibiotic-resistant microorganisms from sanitary sewage sludge produced in two conventional wastewater treatment systems adopted in the West of the State of Paraná, Brazil. Design/methodology/approach The sludge samples were collected for three months from two wastewater treatment plants, totaling six sample points, and sent to the laboratory where the physical-chemical and biological determinations were performed. Findings This work made possible to find that the sludge produced in the sewage treatment plants presents potential risks related to the spread of microorganisms due to the occurrence of resistant isolates of Escherichia coli and Salmonella sp. It was also possible to detect that the largest concentrations of metal ions in the sludge favored the occurrence of bacterial resistance to antibiotics. The occurrence of pathogens, heavy metals and other emerging pollutants in sewage indicates that the sludge requires proper treatment, to provide safe agricultural reuse or disposal. Practical implications The techniques applied for monitoring sludge were effective to check the risk of resistant microorganisms input into the environment. Studies concerning sewage treatment plants’ final effluents can bring additional data about the incorporation of such microorganisms into aquatic environments. Originality/value The results made possible to observe the need to provide post-treatment for the sludge, especially of the sludge obtained from the anaerobic fluidized bed reactor, since the removal of pathogens, as well as the nutrients, is not satisfactory.
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Shibulal, Biji, Saif N. Al-Bahry, Yahya M. Al-Wahaibi, Abdulkader E. Elshafie, Ali S. Al-Bemani, and Sanket J. Joshi. "Microbial Enhanced Heavy Oil Recovery by the Aid of Inhabitant Spore-Forming Bacteria: An Insight Review." Scientific World Journal 2014 (2014): 1–12. http://dx.doi.org/10.1155/2014/309159.
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Crude oil is the major source of energy worldwide being exploited as a source of economy, including Oman. As the price of crude oil increases and crude oil reserves collapse, exploitation of oil resources in mature reservoirs is essential for meeting future energy demands. As conventional recovery methods currently used have become less efficient for the needs, there is a continuous demand of developing a new technology which helps in the upgradation of heavy crude oil. Microbial enhanced oil recovery (MEOR) is an important tertiary oil recovery method which is cost-effective and eco-friendly technology to drive the residual oil trapped in the reservoirs. The potential of microorganisms to degrade heavy crude oil to reduce viscosity is considered to be very effective in MEOR. Earlier studies of MEOR (1950s) were based on three broad areas: injection, dispersion, and propagation of microorganisms in petroleum reservoirs; selective degradation of oil components to improve flow characteristics; and production of metabolites by microorganisms and their effects. Since thermophilic spore-forming bacteria can thrive in very extreme conditions in oil reservoirs, they are the most suitable organisms for the purpose. This paper contains the review of work done with thermophilic spore-forming bacteria by different researchers.
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Doan, Hung K., Viviane N. Ngassam, Sean F. Gilmore, Robin Tecon, Atul N. Parikh, and Johan H. J. Leveau. "Topography-Driven Shape, Spread, and Retention of Leaf Surface Water Impacts Microbial Dispersion and Activity in the Phyllosphere." Phytobiomes Journal 4, no. 3 (January 2020): 268–80. http://dx.doi.org/10.1094/pbiomes-01-20-0006-r.
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To study the impact of lateral variation in surface topography on the microbial colonization of plant leaves, we used a two-step casting process to generate topomimetic “replicasts” in polydimethylsiloxane which faithfully resembled leaf surface topography at submicrometer scale. This process revealed that the shape and size of the phyllotelma—the collective body of standing water on a leaf surface—was a function of wetting method and presence of surface features, in particular leaf veins. The use of dyes and fluorescently labeled bacteria showed that these veins, especially on the abaxial side, contributed to the pooling, retention, and lateral spread of water and microorganisms. Bodies of water along veins acted as conduits that allowed bacterial cells to sense chemicals over distances exceeding their body length by four orders of magnitude. Bacterial survival rates under conditions of low relative humidity were twice as high on leaf replicasts as on flat surfaces, suggesting topography-dependent protection from desiccation. Our findings highlight the need for greater quantitative understanding of the impact of leaf surface topography on phyllotelma connectivity and the outcomes of interactions between microorganisms and with their plant host. Such understanding benefits both theory and practice of phyllosphere microbiology in areas such as foliar disease management and food safety of leafy greens.