Journal articles: 'Yeast bioprocess'

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Mota, Marta N., Paula Múgica, and Isabel Sá-Correia. "Exploring Yeast Diversity to Produce Lipid-Based Biofuels from Agro-Forestry and Industrial Organic Residues." Journal of Fungi 8, no. 7 (2022): 687. http://dx.doi.org/10.3390/jof8070687.

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Exploration of yeast diversity for the sustainable production of biofuels, in particular biodiesel, is gaining momentum in recent years. However, sustainable, and economically viable bioprocesses require yeast strains exhibiting: (i) high tolerance to multiple bioprocess-related stresses, including the various chemical inhibitors present in hydrolysates from lignocellulosic biomass and residues; (ii) the ability to efficiently consume all the major carbon sources present; (iii) the capacity to produce lipids with adequate composition in high yields. More than 160 non-conventional (non-Saccharomyces) yeast species are described as oleaginous, but only a smaller group are relatively well characterised, including Lipomyces starkeyi, Yarrowia lipolytica, Rhodotorula toruloides, Rhodotorula glutinis, Cutaneotrichosporon oleaginosus and Cutaneotrichosporon cutaneum. This article provides an overview of lipid production by oleaginous yeasts focusing on yeast diversity, metabolism, and other microbiological issues related to the toxicity and tolerance to multiple challenging stresses limiting bioprocess performance. This is essential knowledge to better understand and guide the rational improvement of yeast performance either by genetic manipulation or by exploring yeast physiology and optimal process conditions. Examples gathered from the literature showing the potential of different oleaginous yeasts/process conditions to produce oils for biodiesel from agro-forestry and industrial organic residues are provided.

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Valdez Castillo, Mariana, Satinder Kaur Brar, Sonia Arriaga, Jean-François Blais, Michèle Heitz, and Antonio Avalos Ramirez. "Co-Fermentation of Agri-Food Residues Using a Co-Culture of Yeasts as a New Bioprocess to Produce 2-Phenylethanol." Molecules 28, no. 14 (2023): 5536. http://dx.doi.org/10.3390/molecules28145536.

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Whey is a dairy residue generated during the production of cheese and yogurt. Whey contains mainly lactose and proteins, contributing to its high chemical oxygen demand (COD). Current environmental regulations request proper whey disposal to avoid environmental pollution. Whey components can be transformed by yeast into ethanol and biomolecules with aroma and flavor properties, for example, 2-phenyethanol (2PE), highly appreciated in the industry due to its organoleptic and biocidal properties. The present study aimed to valorize agri-food residues in 2PE by developing suitable bioprocess. Cheese whey was used as substrate source, whereas crab headshells, residual soy cake, and brewer’s spent yeast (BSY) were used as renewable nitrogen sources for the yeasts Kluyveromyces marxianus and Debaryomyces hansenii. The BSYs promoted the growth of both yeasts and the production of 2PE in flask fermentation. The bioprocess scale-up to 2 L bioreactor allowed for obtaining a 2PE productivity of 0.04 g2PE/L·h, twofold better productivity results compared to the literature. The bioprocess can save a treatment unit because the whey COD decreased under the detection limit of the analytical method, which is lower than environmental requirements. In this way, the bioprocess prevents environmental contamination and contributes to the circular economy of the dairy industry.

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Bărbulescu, Iuliana Diana, Mihaela Violeta Ghica, Mihaela Begea, et al. "Optimization of the Fermentation Conditions for Brewing Yeast Biomass Production Using the Response Surface Methodology and Taguchi Technique." Agriculture 11, no. 12 (2021): 1237. http://dx.doi.org/10.3390/agriculture11121237.

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Yeast (including brewing yeast) and yeast-based preparations derived from bioprocesses or agroindustrial byproducts represent valuable feed additives and ingredients for ruminants. The optimization of brewing yeast biotechnological processing through fermentation mediated by the brewing yeast strain Saccharomyces pastorianus ssp. carlsbergensis W34/70 was investigated. The cultivation conditions (temperature, pH, carbon source, and nitrogen source) were selected and designed according to a Taguchi fractional experimental plan, with four factors on three levels, and their influence on the evolution of the bioprocess of obtaining the brewing yeast biomass was evaluated. The dependent variables were the yeast biomass amount in wet form, yeast biomass amount in dried form after lyophilization, dried yeast biomass wettability assayed through the contact angle (CA), protein content (PC), and dry matter content (DS). The effects that the experimental conditions had on the system responses were visualized in tridimensional space using the response surface methodology, and the combination of biotechnological parameters that ensured process quality and robustness was then determined using the Taguchi technique through its performance indicator, i.e., the signal-to-noise ratio. By optimizing the biotechnological parameters, this study provides a valuable contribution in the area of brewing yeast biomass processing, with the aim of producing probiotic yeast for ruminant nutrition.

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Novak, Mario, Nenad Marđetko, Antonija Trontel, et al. "Development of an Integrated Bioprocess System for Bioethanol and Arabitol Production from Sugar Beet Cossettes." Food Technology and Biotechnology 62, no. 1 (2024): 89–101. http://dx.doi.org/10.17113/ftb.62.01.24.8230.

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Research background. An innovative integrated bioprocess system for bioethanol production from raw sugar beet cossettes (SBC) and arabitol from remaining exhausted sugar beet cossettes (ESBC) was studied. This integrated three-stage bioprocess system is an example of the biorefinery concept to maximise the use of raw SBC for the production of high value-added products such as sugar alcohols and bioethanol. Experimental approach. The first stage of the integrated bioprocess system was simultaneous sugar extraction from SBC and its alcoholic fermentation to produce bioethanol in an integrated bioreactor system (vertical column bioreactor and stirred tank bioreactor) containing a high-density suspension of yeast Saccharomyces cerevisiae (30 g/L). The second stage was the pretreatment of ESBC with dilute sulfuric acid to release fermentable sugars. The resulting liquid hydrolysate of ESBC was used in the third stage as a nutrient medium for arabitol production by non-Saccharomyces yeasts (Spathaspora passalidarum CBS 10155 and Spathaspora arborariae CBS 11463). Results and conclusions. The obtained results show that the efficiency of bioethanol production increased with increasing temperature and prolonged residence time in the integrated bioreactor system. The maximum bioethanol production efficiency (87.22 %) was observed at a time of 60 min and a temperature of 36 °C. Further increase in residence time (above 60 min) did not result in the significant increase of bioethanol production efficiency. Weak acid hydrolysis was used for ESBC pretreatment and the highest sugar yield was reached at 200 °C and residence time of 1 min. The inhibitors of the weak acid pretreatment were produced below bioprocess inhibition threshold. The use of the obtained liqiud phase of ESBC hydrolysate for the production of arabitol in the stirred tank bioreactor under constant aeration clearly showed that S. passalidarum CBS 10155 with 8.48 g/L of arabitol (YP/S=0.603 g/g and bioprocess productivity of 0.176 g/(L·h)) is a better arabitol producer than Spathaspora arborariae CBS 10155. Novelty and scientific contribution. An innovative integrated bioprocess system for the production of bioethanol and arabitol was developed based on the biorefinery concept. This three-stage bioprocess system shows great potential for maximum use of SBC as a feedstock for bioethanol and arabitol production and it could be an example of a sustainable ‘zero waste’ production system.

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Dumitrache, Corina, Mihaela Violeta Ghica, Mihai Frîncu, et al. "Bioprocess Optimization by Taguchi Design and Response Surface Analysis for Obtaining Active Yeast Used in Vinification." Fermentation 10, no. 8 (2024): 413. http://dx.doi.org/10.3390/fermentation10080413.

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This study presents the behavior of the identified yeast strain S. cerevisiae, isolated from Busuioacă de Bohotin grapes from the Pietroasa winery, during the process of fermentation to obtain dry active yeast biomass for the winemaking process. In this respect, we promoted an optimization strategy for obtaining active dry yeast biomass. The cultivation conditions for micropilot fermentation (temperature, pH, carbon source, and nitrogen source) were selected and designed according to a Taguchi design with four factors and three levels. Reproducibility testing was conducted under specific fermentation parameters: temperature (32 °C), pH (4.5), carbon source (12%), and nitrogen source (0.7%). Following the optimization process, two combinations of cultivation parameters were selected, and one of them, based on the results, was selected for further analysis. Quantitative data were obtained, showing dry yeast biomass (DCW) at 1.39 g/100 mL and protein content at 45.57%. The active yeast was then used in the winemaking process for Tămâioasă Românească and Busuioacă de Bohotin varieties at Pietroasa winery for validation. This optimization aims to facilitate easy and rapid production of fresh wine yeast tailored to the local winemaking practices of Pietroasa winery, with real application potential in other viticultural areas, aligning with the terroir concept.

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Sendrescu, Dorin. "Distribution-Based Identification of Yield Coefficients in a Baker’s Yeast Bioprocess." Mathematical Problems in Engineering 2012 (2012): 1–21. http://dx.doi.org/10.1155/2012/789156.

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A distribution-based identification procedure for estimation of yield coefficients in a baker’s yeast bioprocess is proposed. This procedure transforms a system of differential equations to a system of algebraic equations with respect to unknown parameters. The relation between the state variables is represented by functionals using techniques from distribution theory. A hierarchical structure of identification is used, which allows obtaining a linear algebraic system of equations in the unknown parameters. The coefficients of this algebraic system are functionals depending on the input and state variables evaluated through some test functions from distribution theory. First, only some state equations are evaluated throughout test functions to obtain a set of linear equations in parameters. The results of this first stage of identification are used to express other parameters by linear equations. The process is repeated until all parameters are identified. The performances of the method are analyzed by numerical simulations.

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Mahjoub, M., R. Mosrati, M. Lamotte, C. Fonteix, and I. Marc. "Fuzzy control of baker's yeast fed-batch bioprocess: A robustness study." Food Research International 27, no. 2 (1994): 145–53. http://dx.doi.org/10.1016/0963-9969(94)90156-2.

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Theodosiou, Eleni. "Engineering Strategies for Efficient Bioconversion of Glycerol to Value-Added Products by Yarrowia lipolytica." Catalysts 13, no. 4 (2023): 657. http://dx.doi.org/10.3390/catal13040657.

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Yarrowia lipolytica has been a valuable biotechnological workhorse for the production of commercially important biochemicals for over 70 years. The knowledge gained so far on the native biosynthetic pathways, as well as the availability of numerous systems and synthetic biology tools, enabled not only the regulation and the redesign of the existing metabolic pathways, but also the introduction of novel synthetic ones; further consolidating the position of the yeast in industrial biotechnology. However, for the development of competitive and sustainable biotechnological production processes, bioengineering should be reinforced by bioprocess optimization strategies. Although there are many published reviews on the bioconversion of various carbon sources to value-added products by Yarrowia lipolytica, fewer works have focused on reviewing up-to-date strain, medium, and process engineering strategies with an aim to emphasize the significance of integrated engineering approaches. The ultimate goal of this work is to summarize the necessary knowledge and inspire novel routes to manipulate at a systems level the yeast biosynthetic machineries by combining strain and bioprocess engineering. Due to the increasing surplus of biodiesel-derived waste glycerol and the favored glycerol-utilization metabolic pathways of Y. lipolytica over other carbon sources, the present review focuses on pure and crude glycerol-based biomanufacturing.

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Do, Diem T. Hoang, Chrispian W. Theron, and Patrick Fickers. "Organic Wastes as Feedstocks for Non-Conventional Yeast-Based Bioprocesses." Microorganisms 7, no. 8 (2019): 229. http://dx.doi.org/10.3390/microorganisms7080229.

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Non-conventional yeasts are efficient cell factories for the synthesis of value-added compounds such as recombinant proteins, intracellular metabolites, and/or metabolic by-products. Most bioprocess, however, are still designed to use pure, ideal sugars, especially glucose. In the quest for the development of more sustainable processes amid concerns over the future availability of resources for the ever-growing global population, the utilization of organic wastes or industrial by-products as feedstocks to support cell growth is a crucial approach. Indeed, vast amounts of industrial and commercial waste simultaneously represent an environmental burden and an important reservoir for recyclable or reusable material. These alternative feedstocks can provide microbial cell factories with the required metabolic building blocks and energy to synthesize value-added compounds, further representing a potential means of reduction of process costs as well. This review highlights recent strategies in this regard, encompassing knowledge on catabolic pathways and metabolic engineering solutions developed to endow cells with the required metabolic capabilities, and the connection of these to the synthesis of value-added compounds. This review focuses primarily, but not exclusively, on Yarrowia lipolytica as a yeast cell factory, owing to its broad range of naturally metabolizable carbon sources, together with its popularity as a non-conventional yeast.

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Grahovac, Jovana, Ivana Pajcin, Vanja Vlajkov, et al. "Xanthomonas campestris biocontrol agent: Selection, medium formulation and bioprocess kinetic analysis." Chemical Industry and Chemical Engineering Quarterly, no. 00 (2020): 32. http://dx.doi.org/10.2298/ciceq200508032g.

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Black rot, caused by Xanthomonas campestris pv. campestris, is one of the most important diseases of cruciferous crops which causes significant yield losses. Biological control of black rot by microbial biocontrol agents represents a promising alternative to chemical treatments and good agricultural practices which show only limited success. This study was carried out to assess a potential of different antagonists, including genera Bacillus, Pseudomonas, Lactobacillus, Streptomyces, Saccharomyces and Trichoderma, for biological control of black rot. Cultivation broth samples and their filtrates were examined against seven Xanthomonas campestris strains, isolated from diseased cruciferous plants, using the diffusion-disc method. Bacillus velezensis has showed the highest inhibition zone diameter of 35.62?3.76 mm. Afterwards different combinations of carbon and nitrogen sources were used in cultivation medium to maximize antagonistic activity of Bacillus velezensis. The best combinations were glycerol and yeast extract, lactose and peptone, as well as sucrose and yeast extract, suggesting the potential of biodiesel, dairy and sugar industry effluents in the production of bioactive compounds effective against the black rot pathogen. Validation experiment was performed in a laboratory-scale bioreactor, in order to investigate bioprocess kinetics of biomass growth and carbon source consumption, using cultivation medium containing the optimal carbon and nitrogen source.

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Lisičar, Josipa, Thomas Scheper, and Stéphan Barbe. "Turning Industrial Baker's Yeast Manufacture into a Powerful Zero Discharge Multipurpose Bioprocess." Industrial Biotechnology 13, no. 4 (2017): 184–91. http://dx.doi.org/10.1089/ind.2017.0018.

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Yatsyshyn, Valentyna Y., Dariya V. Fedorovych, and Andriy A. Sibirny. "Metabolic and bioprocess engineering of the yeast Candida famata for FAD production." Journal of Industrial Microbiology & Biotechnology 41, no. 5 (2014): 823–35. http://dx.doi.org/10.1007/s10295-014-1422-7.

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Batic, Martin, and Peter Raspor. "Effect of cultivation mode on a bioprocess for chromium yeast biomass enrichment." Pflügers Archiv - European Journal of Physiology 439, S1 (2000): r073—r075. http://dx.doi.org/10.1007/s004240000096.

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Baric, Martin, and Peter Raspor. "Effect of cultivation mode on a bioprocess for chromium yeast biomass enrichment." Pflügers Archiv - European Journal of Physiology 439, no. 7 (2000): R73—R75. http://dx.doi.org/10.1007/bf03376527.

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Vucurovic, Vesna, Radojka Razmovski, and Mario Rebic. "A corn stem as biomaterial for Saccharomyces cerevisiae cells immobilization for the ethanol production." Chemical Industry and Chemical Engineering Quarterly 14, no. 4 (2008): 235–38. http://dx.doi.org/10.2298/ciceq0804235v.

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This study provides a preliminary contribution to the development of a bioprocess for the production of ethanol using Saccharomyces cerevisiae cells immobilized onto a corn stem. For this purpose, the yeast cells were submitted to the batch tests in situ adsorption onto 0.5 cm long corn stem. Cells immobilization was analyzed by optical microscopy. The number of the yeast cells, fermentation kinetics, the ethanol yield in the presence or the absence of the support in the fermentation medium was investigated. It was determined that the addition of the corn stem led to the abrupt increase of the yeast cells number in substrate, ethanol yield, pH value, a total dissolved salts content and substrate conductivity. The addition of 5 and 10g of the corn stem pith per liter of the medium decreased the amount of residual sugar. The results indicate that a corn stem might be a good carrier for the yeast cell immobilization, and also a cheap alternative recourse of mineral components with the possibility of application for improving ethanol productivities.

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Siller-Sánchez, Arturo, Cristóbal N. Aguilar, Mónica L. Chávez-González, Juan A. Ascacio-Valdés, Deepak Kumar Verma, and Miguel Aguilar-González. "Solid-State Fermentation-Assisted Extraction of Flavonoids from Grape Pomace Using Co-Cultures." Processes 12, no. 9 (2024): 2027. http://dx.doi.org/10.3390/pr12092027.

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Eighty percent of grape production is destined for the wine industry, which generates various types of waste, of which grape pomace is the main one, accounting for 50–60% of waste created during processing. This waste could be a promising source of bioactive compounds (e.g., flavonoids and tannin), which are known for their antioxidant properties. Although these byproducts pose disposal challenges, they can be utilized as a substrate for solid-state fermentation bioprocess using co-cultures, where different microorganisms can interact and complement each other, improving the efficiency of metabolite production or substrate degradation. This study investigates the extraction of phenolic compounds and the antioxidant activity of the compounds from grape pomace in the solid-state fermentation bioprocess, comparing fungal and yeast monocultures, and then exploring the use of two co-cultures (P. stipites/A. niger GH1 and S. cerevisiae/A. niger) on the flavonoid extractive process. Fermentation kinetics were evaluated over 120 h, with sampling done every 12 h. Initially, yeasts were used to reduce the content of simple sugars in the medium, and fungus was added at 24 h into the process due to its ability to produce a broad spectrum of extracellular enzymes, allowing a higher efficiency in substrate degradation. Competition or antagonism during co-culture leads to significantly higher production of compounds, which are recovered using different solvents. The evaluation included phenolic compounds (total polyphenols, condensed tannins, and total flavonoids), antioxidant activity (DPPH●/FRAP), molecular characterization (HPLC-MS), and structural microscopy during the bioprocess. The highest titers obtained were 62.46 g/L for total flavonoids and 32.04 g/L for condensed tannins, using acetone as the solvent in co-culture with P. stipitis after 120 h of fermentation. Characterization identified 38 compounds, highlighting families of flavonols, hydroxybenzoic acids, and hydroxycinnamic acids. The co-culture of P. stipitis and A. niger GH1 significantly improved the extraction yield of bioactive compounds through solid-state fermentation.

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Sena, Hellen Holanda, Michele Alves Sanches, Diego Fernando Silva Rocha, Walter Oliva Pinto Filho Segundo, Érica Simplício de Souza, and João Vicente Braga de Souza. "Production of Biosurfactants by Soil Fungi Isolated from the Amazon Forest." International Journal of Microbiology 2018 (2018): 1–8. http://dx.doi.org/10.1155/2018/5684261.

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Biosurfactants are surface-active compounds that have sparked interest in recent years because of their environmental advantages over conventional surfactants. The aim of this study was to investigate the production of biosurfactants by soil fungi isolated from the Amazon forest. Fungi colonies were isolated from soil samples and screened for biosurfactant production in submerged fermentation. In addition, the influences of bioprocess factors (carbon source, nitrogen source, pH, and fermentation time) were investigated. Finally, the biosurfactant produced was semipurified and submitted to stability tests. One hundred fungal cultures were obtained from the soil samples, identified by micromorphology, and submitted to screening for biosurfactant production. Sixty-one strains produced biosurfactants. The strainPenicillium8CC2 showed the highest emulsification index (54.2%). The optimized bioprocess conditions for biosurfactant production byPenicillium8CC2 were as follows: soybean oil, 20 g/L; yeast extract, 30 g/L; pH 9; duration of 9 days. The semipurified biosurfactant showed stability after heating at 100°C for 60 min and after the addition of 30% NaCl (w/v). Tween 80 (0.2% w/v), a conventional surfactant, was used as the control.

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C.H, Hun. "Bioprocess Development for High Cell Mass Production of the Probiotic Yeast-Kluyveromyces lactis." IOSR Journal of Pharmacy and Biological Sciences 8, no. 3 (2013): 49–59. http://dx.doi.org/10.9790/3008-0834959.

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Zhao, Yan, Xiaobin Yu, Fengtao Zhu, et al. "Effects of Different Winemaking Yeasts on the Composition of Aroma-Active Compounds and Flavor of the Fermented Jujube Wine." Processes 9, no. 6 (2021): 970. http://dx.doi.org/10.3390/pr9060970.

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For the winemaking bioprocess of jujube wine, the selection of optimal starter cultures is one of the major concerns before fermentation. In this study, we investigated the effects of different winemaking yeasts on the composition of aroma-active compounds in the fermented jujube wine and identified the principal components that determine the flavor quality. It showed that the starter winemaking yeasts produced a total of 43 aroma-active compounds, of which esters (e.g., ethyl caprylate, ethyl decanoate, ethyl hexanoate, and phenethyl acetate) contribute more to the wine quality attributes, especially for the improvement of the aroma. Moreover, the composition of aroma-active compounds, for example, the ratio of the content of esters and alcohols, exerts a great impact on the flavor quality of jujube wine. Different starter winemaking yeasts resulted in significant differences in the composition (both species and content) of aroma-active compounds, and thus formed different flavors in the jujube wine. Thus, we propose that screening of a desirable starter winemaking yeast is essential before the fermentation of jujube wine at a large scale, and more considerations should be taken into the resulting composition of aroma-active compounds.

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Febriyanti, Anugerah Eka, Cut Nanda Sari, and Adisyahputra Adisyahputra. "EFEKTIVITAS MEDIA PERTUMBUHAN KHAMIR KOMERSIAL (Saccharomyces cerevisiae) UNTUK FERMENTASI BIOETANOL DARI ECENG GONDOK (Eichhornia crassipes)." BIOMA 12, no. 2 (2017): 112. http://dx.doi.org/10.21009/bioma12(2).6.

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This study aims to find growth medium commercial yeast (S.cerevisiae) and determine the optimum composition of bioethanol fermentation. This research was conducted at the Laboratory of Bioprocess PPPTMGB “LEMIGAS” along May to September 2015. The method used is experiment using a completely randomized design consisting of two treatment. The first treatment is an alternative growth media utilization, namely, tofu liquid waste, coconut water and a mixture of both. The second treatment is the composition of the fermentation with sugar content of 100 ml, 150 ml and 200 ml with the addition of 10 ml starter in each experiment. Data of commercial yeast cell growth (S.cerevisiae) on alternative growth media were analyzed by Anova one way. The results showed that there was an interaction of commercial yeast cell growth (S.cerevisiae) on alternative growth media. Post-hoc test showed the alternative media that consists of a mixture of tofu liquid waste and coconut water produce the highest commercial yeast cell growth at 25,8 x107 with a 7.62 log value (cells/ml). The most optimum of bioethanol produced in the fermentation process is on sugar 100 ml by the addition of 10 ml starter acquire as much as 45 ml of ethanol content.

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Rašković, P., A. Anastasovski, Lj Markovska, and V. Meško. "Process integration in bioprocess indystry: waste heat recovery in yeast and ethyl alcohol plant." Energy 35, no. 2 (2010): 704–17. http://dx.doi.org/10.1016/j.energy.2009.11.020.

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Lahtvee, Petri-Jaan, Rahul Kumar, Björn M. Hallström, and Jens Nielsen. "Adaptation to different types of stress converge on mitochondrial metabolism." Molecular Biology of the Cell 27, no. 15 (2016): 2505–14. http://dx.doi.org/10.1091/mbc.e16-03-0187.

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Yeast cell factories encounter physical and chemical stresses when used for industrial production of fuels and chemicals. These stresses reduce productivity and increase bioprocess costs. Understanding the mechanisms of the stress response is essential for improving cellular robustness in platform strains. We investigated the three most commonly encountered industrial stresses for yeast (ethanol, salt, and temperature) to identify the mechanisms of general and stress-specific responses under chemostat conditions in which specific growth rate–dependent changes are eliminated. By applying systems-level analysis, we found that most stress responses converge on mitochondrial processes. Our analysis revealed that stress-specific factors differ between applied stresses; however, they are underpinned by an increased ATP demand. We found that when ATP demand increases to high levels, respiration cannot provide sufficient ATP, leading to onset of respirofermentative metabolism. Although stress-specific factors increase ATP demand for cellular growth under stressful conditions, increased ATP demand for cellular maintenance underpins a general stress response and is responsible for the onset of overflow metabolism.

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Nandini, Allure, D. N. Madhusudhan, and Agsar Dayanand. "Enhanced Production, Purification and Characterization of Alkaline Keratinase from Streptomyces minutiscleroticus DNA38." International Letters of Natural Sciences 43 (July 2015): 27–37. http://dx.doi.org/10.18052/www.scipress.com/ilns.43.27.

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A thermo tolerant, feather-degrading, newly isolated actinobacterial strain Streptomyces minutiscleroticus DNA38 was investigated for its ability to produce keratinase. Maximum production (283.4 IU) of keratinase by Streptomyces minutiscleroticus DNA38 in starch chicken feathers medium under submerged bioprocess was observed at optimized conditions of pH 9.0 of the medium and 45 °C incubation temperature. Further, an enhanced production (435.8 IU) of keratinase was achieved employing response surface methodology. Combined interactive effect of starch (7.50 g/L), yeast extract (0.74 g/L) and chicken feathers (7.50 g/L) were found to be the critical process variables for enhanced production under central composite design. Chicken feathers showed a direct action and addition of starch and yeast extract to the medium proved effective for a significant increase in the production of keratinase. The purified keratinase was monomeric and had a molecular mass of 29 kDa. The enzyme activity was significantly inhibited after pH 9.0 and temperature 50 °C.

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Nandini, Allure, D. N. Madhusudhan, and Agsar Dayanand. "Enhanced Production, Purification and Characterization of Alkaline Keratinase from <i>Streptomyces minutiscleroticus </i>DNA38." International Letters of Natural Sciences 43 (July 22, 2015): 27–37. http://dx.doi.org/10.56431/p-zpi3k0.

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A thermo tolerant, feather-degrading, newly isolated actinobacterial strain Streptomyces minutiscleroticus DNA38 was investigated for its ability to produce keratinase. Maximum production (283.4 IU) of keratinase by Streptomyces minutiscleroticus DNA38 in starch chicken feathers medium under submerged bioprocess was observed at optimized conditions of pH 9.0 of the medium and 45 °C incubation temperature. Further, an enhanced production (435.8 IU) of keratinase was achieved employing response surface methodology. Combined interactive effect of starch (7.50 g/L), yeast extract (0.74 g/L) and chicken feathers (7.50 g/L) were found to be the critical process variables for enhanced production under central composite design. Chicken feathers showed a direct action and addition of starch and yeast extract to the medium proved effective for a significant increase in the production of keratinase. The purified keratinase was monomeric and had a molecular mass of 29 kDa. The enzyme activity was significantly inhibited after pH 9.0 and temperature 50 °C.

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Nisiotou, Aspasia A., Apostolos E. Spiropoulos, and George-John E. Nychas. "Yeast Community Structures and Dynamics in Healthy and Botrytis-Affected Grape Must Fermentations." Applied and Environmental Microbiology 73, no. 21 (2007): 6705–13. http://dx.doi.org/10.1128/aem.01279-07.

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ABSTRACT Indigenous yeast population dynamics during the fermentation of healthy and Botrytis-affected grape juice samples from two regions in Greece, Attica and Arcadia, were surveyed. Species diversity was evaluated by using restriction fragment length polymorphism and sequence analyses of the 5.8S internal transcribed spacer and the D1/D2 ribosomal DNA (rDNA) regions of cultivable yeasts. Community-level profiles were also obtained by direct analysis of fermenting samples through denaturing gradient gel electrophoresis of 26S rDNA amplicons. Both approaches revealed structural divergences in yeast communities between samples of different sanitary states or geographical origins. In all cases, Botrytis infection severely perturbed the bioprocess of fermentation by dramatically altering species heterogeneity and succession during the time course. At the beginning and middle of fermentations, Botrytis-affected samples possessed higher levels of biodiversity than their healthy counterparts, being enriched with fermentative and/or spoilage species, such as Zygosaccharomyces bailii and Issatchenkia spp. or Kluyveromyces dobzhanskii and Kazachstania sp. populations that have not been reported before for wine fermentations. Importantly, Botrytis-affected samples exposed discrete final species dominance. Selection was not species specific, and two different populations, i.e., Saccharomyces cerevisiae in samples from Arcadia and Z. bailii in samples from Attica, could be recovered at the end of Botrytis-affected fermentations. The governing of wine fermentations by Z. bailii is reported for the first time and could elucidate the origins and role of this particular spoilage microbe for the wine industry. This is the first survey to compare healthy and Botrytis-affected spontaneous fermentations by using both culture-based and -independent molecular methods in an attempt to further illuminate the complex yeast ecology of grape must fermentations.

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Hu, Peng, Sagar Chakraborty, Amit Kumar, et al. "Integrated bioprocess for conversion of gaseous substrates to liquids." Proceedings of the National Academy of Sciences 113, no. 14 (2016): 3773–78. http://dx.doi.org/10.1073/pnas.1516867113.

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In the quest for inexpensive feedstocks for the cost-effective production of liquid fuels, we have examined gaseous substrates that could be made available at low cost and sufficiently large scale for industrial fuel production. Here we introduce a new bioconversion scheme that effectively converts syngas, generated from gasification of coal, natural gas, or biomass, into lipids that can be used for biodiesel production. We present an integrated conversion method comprising a two-stage system. In the first stage, an anaerobic bioreactor converts mixtures of gases of CO2 and CO or H2 to acetic acid, using the anaerobic acetogen Moorella thermoacetica. The acetic acid product is fed as a substrate to a second bioreactor, where it is converted aerobically into lipids by an engineered oleaginous yeast, Yarrowia lipolytica. We first describe the process carried out in each reactor and then present an integrated system that produces microbial oil, using synthesis gas as input. The integrated continuous bench-scale reactor system produced 18 g/L of C16-C18 triacylglycerides directly from synthesis gas, with an overall productivity of 0.19 g⋅L−1⋅h−1 and a lipid content of 36%. Although suboptimal relative to the performance of the individual reactor components, the presented integrated system demonstrates the feasibility of substantial net fixation of carbon dioxide and conversion of gaseous feedstocks to lipids for biodiesel production. The system can be further optimized to approach the performance of its individual units so that it can be used for the economical conversion of waste gases from steel mills to valuable liquid fuels for transportation.

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Soares, Raiane C., Teresa C. Zangirolami, Raquel L. C. Giordano, Mekonnen M. Demeke, Johan M. Thevelein, and Thais S. Milessi. "Cell Immobilization Using Alginate-Based Beads as a Protective Technique against Stressful Conditions of Hydrolysates for 2G Ethanol Production." Polymers 14, no. 12 (2022): 2400. http://dx.doi.org/10.3390/polym14122400.

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The development of biorefineries brings the necessity of an efficient consumption of all sugars released from biomasses, including xylose. In addition, the presence of inhibitors in biomass hydrolysates is one of the main challenges in bioprocess feasibility. In this study, the application of Ca-alginate hybrid gels in the immobilization of xylose-consuming recombinant yeast was explored with the aim of improving the tolerance of inhibitors. The recombinant yeast Saccharomyces cerevisiae GSE16-T18SI.1 (T18) was immobilized in Ca-alginate and Ca-alginate–chitosan hybrid beads, and its performance on xylose fermentation was evaluated in terms of tolerance to different acetic acid concentrations (0–12 g/L) and repeated batches of crude sugarcane bagasse hemicellulose hydrolysate. The use of the hybrid gel improved yeast performance in the presence of 12 g/L of acetic acid, achieving 1.13 g/L/h of productivity and reaching 75% of the theoretical ethanol yield, with an improvement of 32% in the xylose consumption rate (1:1 Vbeads/Vmedium, 35 °C, 150 rpm and pH 5.2). The use of hybrid alginate–chitosan gel also led to better yeast performance at crude hydrolysate, yielding one more batch than the pure-alginate beads. These results demonstrate the potential of a hybrid gel as an approach that could increase 2G ethanol productivity and allow cell recycling for a longer period.

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Kallis, Michalis, Konstantinos Sideris, Nikolaos Kopsahelis, et al. "Pistacia terebinthus Resin as Yeast Immobilization Support for Alcoholic Fermentation." Foods 8, no. 4 (2019): 127. http://dx.doi.org/10.3390/foods8040127.

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A natural resin retrieved from Pistacia terebinthus tree was evaluated as an immobilization carrier of Saccharomyces cerevisiae AXAZ-1 cells targeting successive fermentation batches of sugar synthetic mediums. Fermentation times below 54 h were recorded at temperatures 28–14 °C. In total, 147 compounds were detected using gas chromatography-mass spectrometry (GC-MS) analysis, including alcohols, esters, ketones, aldehydes, acids, and terpenes. Principal component analysis indicated that the state of cells (free/immobilized) and the fermentation temperature primarily affected terpenes’ composition. Importantly, no spoilage of the fermented beverages was noted during 90 days of storage at room temperature, most likely due to the high content of extracted terpenoids and phenols (up to 579.01 mg L−1 and 171.8 mg gallic acid equivalent L−1, respectively). Likewise, the developed novel biocatalyst (yeast cells immobilized within Pistacia terebinthus resin) was suitable for the production of low alcohol beverages with an enhanced aromatic profile. The obtained results revealed that the proposed bioprocess shows great commercialization potential in the new fast-growing low-alcohol beverages sector.

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Vičević, Renata, Marko Božinović, Nikolina Zekić, et al. "Development of a Two-Stage Bioprocess for the Production of Bioethanol from the Acid Hydrolysate of Brewer’s Spent Grain." Energies 17, no. 16 (2024): 3975. http://dx.doi.org/10.3390/en17163975.

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Bioethanol, an alcohol produced by microbial fermentation, is traditionally produced from sugar-rich plants such as sugar cane, sugar beet and maize. However, there is growing interest in the use of lignocellulose, an abundant and inexpensive renewable energy source, as a potential substitute for the production of biofuels and biochemicals. Yeast Saccharomyces cerevisiae, which is commonly used for ethanol fermentation, cannot cope with lignocellulose due to a lack of lignocellulolytic enzymes and the inefficient functioning of the pentose phosphate pathway. The aim of this research was to isolate yeasts that can efficiently produce bioethanol and valuable byproducts from both glucose and xylose in a two-stage fermentation process using brewer’s spent grains. This approach should maximize sugar utilization and improve the economic viability of bioethanol production while contributing to waste valorization and sustainability. Kluyveromyces marxianus and Candida krusei were identified and tested with different initial concentrations of glucose and xylose. The results showed that both yeasts produced bioethanol from glucose but were inefficient with xylose, yielding valuable compounds, such as 2,3-butanediol and glycerol instead. A two-stage fermentation was then carried out with weak acidic hydrolysate from brewer’s spent grain. In the first stage, glucose was fermented by S. cerevisiae to produce bioethanol; in the second stage, xylose was fermented by K. marxianus and C. krusei to obtain other valuable products.

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Mapelli, Valeria, Peter R. Hillestrøm, Emese Kápolna, Erik H. Larsen, and Lisbeth Olsson. "Metabolic and bioprocess engineering for production of selenized yeast with increased content of seleno-methylselenocysteine." Metabolic Engineering 13, no. 3 (2011): 282–93. http://dx.doi.org/10.1016/j.ymben.2011.03.001.

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Wang, Da, Fu-Li Li, and Shi-An Wang. "A one-step bioprocess for production of high-content fructo-oligosaccharides from inulin by yeast." Carbohydrate Polymers 151 (October 2016): 1220–26. http://dx.doi.org/10.1016/j.carbpol.2016.06.059.

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dos Reis, Guilherme Anacleto, Brigitte Sthepani Orozco Colonia, Walter Jose Martínez-Burgos, et al. "Sustainable Omega-3 Lipid Production from Agro-Industrial By-Products Using Thraustochytrids: Enabling Process Development, Optimization, and Scale-Up." Foods 13, no. 22 (2024): 3646. http://dx.doi.org/10.3390/foods13223646.

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Thraustochytrids are emerging as a valuable biomass source for high-quality omega-3 polyunsaturated fatty acids (PUFAs), crucial for both human and animal nutrition. This research focuses on cultivating Schizochytrium limacinum SR21 using cost-effective agro-industrial by-products, namely sugarcane molasses (SCM), corn steep liquor (CSL), and residual yeast cream (RYC), to optimize biomass and lipid production through a comprehensive multistep bioprocess. The study involved optimization experiments in shake flasks and stirred-tank bioreactors, where we evaluated biomass, lipid content, and DHA yields. Shake flask optimization resulted in significant enhancements in biomass, lipid content, and lipid production by factors of 1.12, 1.72, and 1.92, respectively. In a 10 L stirred-tank bioreactor, biomass surged to 39.29 g/L, lipid concentration increased to 14.98 g/L, and DHA levels reached an impressive 32.83%. The optimal concentrations identified were 66 g/L of SCM, 24.5 g/L of CSL, and 6 g/L of RYC, achieving a desirability index of 0.87, aimed at maximizing biomass and lipid production. This study shows that agro-industrial by-products can be effective and low-cost substrates for producing lipids using thraustochytrids, offering a sustainable option for omega-3 PUFA production. The findings support future improvements in bioprocesses and potential uses of thraustochytrid biomass in food fortification, dietary supplements, nutraceuticals, and as vegan omega-3 sources.

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Rani, Pushpa, Bijender Singh, and Santosh Kumar Tiwari. "Bacteriocin Production by Lactiplantibacillus plantarum LD1 in Solid-State Fermentation Using Lignocellulosic Substrates." Fermentation 11, no. 4 (2025): 233. https://doi.org/10.3390/fermentation11040233.

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In this study, solid-state fermentation for growth and bacteriocin production by Lactiplantibacillus plantarum LD1 was carried out using wheat bran, a lignocellulosic substrate. This is the first report showing bacteriocin production using L. plantarum LD1 in solid-state fermentation. Wheat bran supported higher production of bacteriocin (391.69 ± 12.58 AU/mL) than other substrates. Appropriate conditions were achieved using statistical designs. Significant factors identified by Plackett–Burman Design and their interactions were studied using response surface methodology. Enhanced production of bacteriocin (582.86 ± 0.87 AU/mL) and optimal growth (log10 CFU/mL 8.56 ± 0.42) were attained in wheat bran medium supplemented with peptone (1.13%), yeast extract (1.13%), glucose (1.56%), and tri-ammonium citrate (0.50%). Growth in non-optimized medium (MRS) was almost similar (log10 CFU/mL 8.15 ± 0.20), but the bacteriocin production level was lower (391.69 ± 0.58 AU/mL). Bacteriocin production was sustainable using varied quantities of wheat bran, showing the suitability of the optimized bioprocess for large-scale production. The cost for bacteriocin production in the optimized medium was found to be 444,583.60 AU/USD, which is about 4 times more economical than the cost of the commercial MRS medium, 121,497.18 AU/USD). Thus, an almost 1.5-fold improvement in bacteriocin production was achieved using wheat bran as the substrate. The cost of the production medium was reduced by approximately 25%, making the bioprocess economical.

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Bertacchi, Stefano, Chiara Cantù, Danilo Porro, and Paola Branduardi. "Optimization of Carotenoids Production from Camelina sativa Meal Hydrolysate by Rhodosporidium toruloides." Fermentation 7, no. 4 (2021): 208. http://dx.doi.org/10.3390/fermentation7040208.

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Several compounds on the market derive from petrochemical synthesis, and carotenoids are no exception. Nonetheless, since their applications in the food, feed and cosmetic sectors, and because of sustainability issues, carotenoids of natural origin are desirable. Carotenoids can be extracted from several plants but also from carotenogenic microorganisms, among which are yeasts. Nonetheless, to meet sustainability criteria, the substrate used for yeast cultivation has to be formulated from residual biomasses. For these reasons, we deploy the yeast, Rhodosporidium toruloides, to obtain carotenoids from Camelina sativa meal, an underrated lignocellulosic biomass. Its enzymatic hydrolysis ensures the release of the sugars, as well as of the other nutrients necessary to sustain the process. We therefore separately optimized enzymatic and biomass loadings, and calculated the yields and productivities of the obtained carotenoids. The best conditions (9% w/v biomass, 0.56% w/wbiomass enzymes) were tested in different settings, in which the fermentation was performed separately or simultaneously with hydrolysis, resulting in a similar production of carotenoids. In order to collect quantitative data under controlled chemo-physical parameters, the process was implemented in stirred-tank bioreactors, obtaining 3.6 ± 0.69 mg/L of carotenoids; despite the volumetric and geometric change, the outcomes were consistent with results from the fermentation of shake flasks. Therefore, these data pave the way to evaluate a potential future industrialization of this bioprocess, considering the opportunity to optimize the use of different amounts of biomass and enzyme loading, as well as the robustness of the process in the bioreactor.

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Selişteanu, D., E. Petre, M. Roman, and D. Şendrescu. "Estimation of kinetic rates in a baker's yeast fed-batch bioprocess by using non-linear observers." IET Control Theory & Applications 6, no. 2 (2012): 243. http://dx.doi.org/10.1049/iet-cta.2011.0067.

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Wetzel, David, Andreas Barbian, Volker Jenzelewski, Gerhard Schembecker, Juliane Merz, and Michael Piontek. "Bioprocess optimization for purification of chimeric VLP displaying BVDV E2 antigens produced in yeast Hansenula polymorpha." Journal of Biotechnology 306 (December 2019): 203–12. http://dx.doi.org/10.1016/j.jbiotec.2019.10.008.

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Matos, Ítalo Thiago Silveira Rocha, Vanderly Andrade de Souza, Giovana do Rosário D’Angelo, Spartaco Astolfi Filho, Edson Júnior do Carmo, and Marcos José Salgado Vital. "Yeasts with Fermentative Potential Associated with Fruits of Camu-Camu (Myrciaria dubia, Kunth) from North of Brazilian Amazon." Scientific World Journal 2021 (December 3, 2021): 1–6. http://dx.doi.org/10.1155/2021/9929059.

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Considering the high biotechnological potential of yeasts associated to edible fruits, a screening for these microorganisms, capable of alcoholic fermentation, was performed in ripe fruits of camu-camu (Myrciaria dubia, Kunth). The fruits were collected from north of Brazilian Amazon, in the floodplain of the Cauamé River. Yeasts were isolated, and fermentation capability was evaluated using Durham tubes. Quantitative assays were performed to calculate ethanol yield (g g−1), specific growth rate (h−1), and ethanol productivity (g L−1·h−1). Taxonomic identification was performed by ribosomal gene nucleotide sequence analysis by alignment using BLASTN. A total of fifteen yeast colonies were isolated, and three of them presented promising ability to ferment glucose to ethanol. These isolates were identified as Candida orthopsilosis, Pichia kudriavzevii, and Meyerozyma caribbica. When cultured in broth containing 180 g·L−1 of glucose, M. caribbica CC003 reached 91.7 percent of the maximum theoretical ethanol concentration (84.4 g·L−1), presenting an ethanol yield and productivity of 0.4688 g·g−1 and 0.781 g·L−1·h−1, respectively. These results indicate a promising potential of this isolate for bioprocess applications. This paper is a rare report of C. orthopsilosis with endophytic habit because most of the references indicate it as a human pathogen. Besides this, M. caribbica is a promising fermenter for alcoholic beverages due to its osmotolerance and high ethanol yield. This is the first paper reporting endophytic yeasts associated with fruits of Myrciaria dubia.

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Brittin, Nathaniel J., David J. Aceti, Doug R. Braun, et al. "Dereplication of Natural Product Antifungals via Liquid Chromatography–Tandem Mass Spectrometry and Chemical Genomics." Molecules 30, no. 1 (2024): 77. https://doi.org/10.3390/molecules30010077.

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Recently expanded reports of multidrug-resistant fungal infections underscore the need to develop new and more efficient methods for antifungal drug discovery. A ubiquitous problem in natural product drug discovery campaigns is the rediscovery of known compounds or their relatives; accordingly, we have integrated Liquid Chromatography–Tandem Mass Spectrometry (LC-MS/MS) for structural dereplication and Yeast Chemical Genomics for bioprocess evaluation into a screening platform to identify such compounds early in the screening process. We identified 450 fractions inhibiting Candida albicans and the resistant strains of C. auris and C. glabrata among more than 40,000 natural product fractions. LC-MS/MS and chemical genomics were then used to identify those with known chemistry and mechanisms of action. The parallel deployment of these orthogonal methods improved the detection of unwanted compound classes over the methods applied individually.

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Wang, Hang, Qingfeng Dong, Chun Meng, Xian ai Shi, and Yanghao Guo. "A continuous and adsorptive bioprocess for efficient production of the natural aroma chemical 2-phenylethanol with yeast." Enzyme and Microbial Technology 48, no. 4-5 (2011): 404–7. http://dx.doi.org/10.1016/j.enzmictec.2011.01.006.

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Sourabié, A., C. Navas, R. Thiam, et al. "BioProcess optimization through yeast-derived nutrients careful selection is key for probiotics and recombinant proteins industrial manufacturing." New Biotechnology 44 (October 2018): S18. http://dx.doi.org/10.1016/j.nbt.2018.05.151.

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Reiter, Alexander, Jian Asgari, Wolfgang Wiechert, and Marco Oldiges. "Metabolic Footprinting of Microbial Systems Based on Comprehensive In Silico Predictions of MS/MS Relevant Data." Metabolites 12, no. 3 (2022): 257. http://dx.doi.org/10.3390/metabo12030257.

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Metabolic footprinting represents a holistic approach to gathering large-scale metabolomic information of a given biological system and is, therefore, a driving force for systems biology and bioprocess development. The ongoing development of automated cultivation platforms increases the need for a comprehensive and rapid profiling tool to cope with the cultivation throughput. In this study, we implemented a workflow to provide and select relevant metabolite information from a genome-scale model to automatically build an organism-specific comprehensive metabolome analysis method. Based on in-house literature and predicted metabolite information, the deduced metabolite set was distributed in stackable methods for a chromatography-free dilute and shoot flow-injection analysis multiple-reaction monitoring profiling approach. The workflow was used to create a method specific for Saccharomyces cerevisiae, covering 252 metabolites with 7 min/sample. The method was validated with a commercially available yeast metabolome standard, identifying up to 74.2% of the listed metabolites. As a first case study, three commercially available yeast extracts were screened with 118 metabolites passing quality control thresholds for statistical analysis, allowing to identify discriminating metabolites. The presented methodology provides metabolite screening in a time-optimised way by scaling analysis time to metabolite coverage and is open to other microbial systems simply starting from genome-scale model information.

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Barbosa-Hernández, Edwin J., Jorge E. Pliego-Sandoval, Anne Gschaedler-Mathis та ін. "Monitoring β-Fructofuranosidase Activity through Kluyveromyces marxianus in Bioreactor Using a Lab-Made Sequential Analysis System". Fermentation 9, № 11 (2023): 963. http://dx.doi.org/10.3390/fermentation9110963.

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The yeast Kluyveromyces marxianus has shown the potential to produce β-fructofuranosidases, which are enzymes capable of hydrolyzing β-fructofuranosides links of fructans to obtain fructooligosaccharides. The thriving market for fructose syrup and the quality standards imposed by food and pharmaceutical industries have generated an increased search for improved, monitored, and controlled production processes. Monitoring β-fructofuranosidase activity in a bioprocess requires the use of adequate sensors and the processing of information using efficient software algorithms; nevertheless, currently, such a sensor does not exist for this purpose. In this contribution, a sequential injection analysis system (SIA) developed in our laboratory was adapted to monitor at-line β-fructofuranosidase activity produced by the yeast K. marxianus. Samples were taken out automatically from the bioreactor and analyzed using 3,5-dinitrosalicylic (DNS). An algorithm was designed to operate the overall components of the lab-made SIA system. The enzymatic activity error obtained with the automatic SIA compared to the off-line laboratory determinations varied from 0.07% at high enzyme concentrations to 20.39% at low β-fructofuranosidase activity. Further development is required to improve the performance of the lab-made SIA system; nevertheless, such a device must be considered as a potential method for monitoring β-fructofuranosidase activity in real time.

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Geiser, Elena, Michèle Reindl, Lars M. Blank, Michael Feldbrügge, Nick Wierckx, and Kerstin Schipper. "Activating Intrinsic Carbohydrate-Active Enzymes of the Smut Fungus Ustilago maydis for the Degradation of Plant Cell Wall Components." Applied and Environmental Microbiology 82, no. 17 (2016): 5174–85. http://dx.doi.org/10.1128/aem.00713-16.

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ABSTRACTThe microbial conversion of plant biomass to valuable products in a consolidated bioprocess could greatly increase the ecologic and economic impact of a biorefinery. Current strategies for hydrolyzing plant material mostly rely on the external application of carbohydrate-active enzymes (CAZymes). Alternatively, production organisms can be engineered to secrete CAZymes to reduce the reliance on externally added enzymes. Plant-pathogenic fungi have a vast repertoire of hydrolytic enzymes to sustain their lifestyle, but expression of the corresponding genes is usually highly regulated and restricted to the pathogenic phase. Here, we present a new strategy in using the biotrophic smut fungusUstilago maydisfor the degradation of plant cell wall components by activating its intrinsic enzyme potential during axenic growth. This fungal model organism is fully equipped with hydrolytic enzymes, and moreover, it naturally produces value-added substances, such as organic acids and biosurfactants. To achieve the deregulated expression of hydrolytic enzymes during the industrially relevant yeast-like growth in axenic culture, the native promoters of the respective genes were replaced by constitutively active synthetic promoters. This led to an enhanced conversion of xylan, cellobiose, and carboxymethyl cellulose to fermentable sugars. Moreover, a combination of strains with activated endoglucanase and β-glucanase increased the release of glucose from carboxymethyl cellulose and regenerated amorphous cellulose, suggesting that mixed cultivations could be a means for degrading more complex substrates in the future. In summary, this proof of principle demonstrates the potential applicability of activating the expression of native CAZymes from phytopathogens in a biocatalytic process.IMPORTANCEThis study describes basic experiments that aim at the degradation of plant cell wall components by the smut fungusUstilago maydis. As a plant pathogen, this fungus contains a set of lignocellulose-degrading enzymes that may be suited for biomass degradation. However, its hydrolytic enzymes are specifically expressed only during plant infection. Here, we provide the proof of principle that these intrinsic enzymes can be synthetically activated during the industrially relevant yeast-like growth. The fungus is known to naturally synthesize valuable compounds, such as itaconate or glycolipids. Therefore, it could be suited for use in a consolidated bioprocess in which more complex and natural substrates are simultaneously converted to fermentable sugars and to value-added compounds in the future.

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Bustos, Cristina, Johan Quezada, Rhonda Veas, et al. "Advances in Cell Engineering of the Komagataella phaffii Platform for Recombinant Protein Production." Metabolites 12, no. 4 (2022): 346. http://dx.doi.org/10.3390/metabo12040346.

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Komagataella phaffii (formerly known as Pichia pastoris) has become an increasingly important microorganism for recombinant protein production. This yeast species has gained high interest in an industrial setting for the production of a wide range of proteins, including enzymes and biopharmaceuticals. During the last decades, relevant bioprocess progress has been achieved in order to increase recombinant protein productivity and to reduce production costs. More recently, the improvement of cell features and performance has also been considered for this aim, and promising strategies with a direct and substantial impact on protein productivity have been reported. In this review, cell engineering approaches including metabolic engineering and energy supply, transcription factor modulation, and manipulation of routes involved in folding and secretion of recombinant protein are discussed. A lack of studies performed at the higher-scale bioreactor involving optimisation of cultivation parameters is also evidenced, which highlights new research aims to be considered.

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Kobayashi, Fumihisa, and Yoshitoshi Nakamura. "Effect of repressor gene on stability of bioprocess with continuous conversion of starch into ethanol using recombinant yeast." Biochemical Engineering Journal 18, no. 2 (2004): 133–41. http://dx.doi.org/10.1016/j.bej.2003.08.001.

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Pajcin, Ivana, Vanja Vlajkov, Dragoljub Cvetkovic, et al. "Selection of antagonists for biocontrol of Xanthomonas euvesicatoria." Acta Periodica Technologica, no. 51 (2020): 181–89. http://dx.doi.org/10.2298/apt2051181p.

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Xanthomonas euvesicatoria is a worldwide causer of pepper bacterial spot, a bacterial plant disease responsible for massive losses of fresh pepper fruits. Considering the current problems in management of bacterial plant diseases, biological control using antagonistic microbial strains with high potential for plant pathogens suppression emerges as a possible solution. The aim of this study was to select suitable antagonists for suppression of X. euvesicatoria among the bacteria, yeast and fungi from the genera Pseudomonas, Lactobacillus, Saccharomyces and Trichoderma, based on in vitro antimicrobial activity testing using the diffusion disc method. The results of this study have revealed that cultivation broth samples of the antagonists Lactobacillus MK3 and Trichoderma reseii QM 9414, as well as supernatant samples of the antagonist Pseudomonas aeruginosa I128, have showed significant potential to be applied in biological control of X. euvesicatoria. Further research would be required to formulate suitable cultivation medium and optimize bioprocess conditions for production of the proposed pepper bacterial spot biocontrol agents.

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Pegu, Bhaba Kumar, Limpon Bora, Jyoti Prava Engty, and Devid Kardong. "Impact of submerged culture different parameters on growth and naringinase activity of Bacillus amyloliquefaciens D1 isolated from citrus gardens of North-East India." ECOLOGY, ENVIRONMENT AND CONSERVATION 30, Suppl (2024): S540—S548. http://dx.doi.org/10.53550/eec.2024.v30i05s.082.

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The study aims at screening, isolation, and characterization of naringinase enzyme producing bacterial strains from soil samples. In this study, 45 bacterial isolates were screened for naringinase activity, and among them, 20 bacterial isolates are found to be capable of naringinase production in liquid mineral medium. Bacterial isolate D1 exhibited the highest naringinase activity in liquid mineral medium. Based on the morphological, biochemical, fatty acid profile, and molecular characterization, bacterial isolate D1 was identified as Bacillus amyloliquefaciens. Impact of different submerged culture parameters were evaluated in different experimental conditions. The study revealed that 48 hrs of incubation periods, pH 6.0 and temperature 350 C is optimal for naringinase activity when the culture medium is supplemented with starch and yeast extract as carbon and nitrogen sources. Thus, it can be concluded that due to the potential naringinase activity of the strain Bacillus amyloliquefaciens D1, further the identifying strain may be used in citrus processing and bioprocess industries upon large scale field applications.

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Pegu, Bhaba Kumar, Limpon Bora, Jyoti Prava Engty, and Devid Kardong. "Impact of submerged culture different parameters on growth and naringinase activity of Bacillus amyloliquefaciens D1 isolated from citrus gardens of North-East India." Ecology, Environment and Conservation 31, Suppl (2025): S177—S185. https://doi.org/10.53550/eec.2025.v31i01s.032.

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The study aims at screening, isolation, and characterization of naringinase enzyme producing bacterial strains from soil samples. In this study, 45 bacterial isolates were screened for naringinase activity, and among them, 20 bacterial isolates are found to be capable of naringinase production in liquid mineral medium. Bacterial isolate D1 exhibited the highest naringinase activity in liquid mineral medium. Based on the morphological, biochemical, fatty acid profile, and molecular characterization, bacterial isolate D1 was identified as Bacillus amyloliquefaciens. Impact of different submerged culture parameters were evaluated in different experimental conditions. The study revealed that 48 hrs of incubation periods, pH 6.0 and temperature 35 0 C is optimal for naringinase activity when the culture medium is supplemented with starch and yeast extract as carbon and nitrogen sources. Thus, it can be concluded that due to the potential naringinase activity of the strain Bacillus amyloliquefaciens D1, further the identifying strain may be used in citrus processing and bioprocess industries upon large scale field applications.

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Berbegal, Carmen, Iuliia Khomenko, Pasquale Russo, et al. "PTR-ToF-MS for the Online Monitoring of Alcoholic Fermentation in Wine: Assessment of VOCs Variability Associated with Different Combinations of Saccharomyces/Non-Saccharomyces as a Case-Study." Fermentation 6, no. 2 (2020): 55. http://dx.doi.org/10.3390/fermentation6020055.

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The management of the alcoholic fermentation (AF) in wine is crucial to shaping product quality. Numerous variables (e.g., grape varieties, yeast species/strains, technological parameters) can affect the performances of this fermentative bioprocess. The fact that these variables are often interdependent, with a high degree of interaction, leads to a huge ‘oenological space’ associated with AF that scientists and professionals have explored to obtain the desired quality standards in wine and to promote innovation. This challenge explains the high interest in approaches tested to monitor this bioprocess including those using volatile organic compounds (VOCs) as target molecules. Among direct injection mass spectrometry approaches, no study has proposed an untargeted online investigation of the diversity of volatiles associated with the wine headspace. This communication proposed the first application of proton-transfer reaction-mass spectrometry coupled to a time-of-flight mass analyzer (PTR-ToF-MS) to follow the progress of AF and evaluate the impact of the different variables of wine quality. As a case study, the assessment of VOC variability associated with different combinations of Saccharomyces/non-Saccharomyces was selected. The different combinations of microbial resources in wine are among the main factors susceptible to influencing the content of VOCs associated with the wine headspaces. In particular, this investigation explored the effect of multiple combinations of two Saccharomyces strains and two non-Saccharomyces strains (belonging to the species Metschnikowia pulcherrima and Torulaspora delbrueckii) on the content of VOCs in wine, inoculated both in commercial grape juice and fresh grape must. The results demonstrated the possible exploitation of non-invasive PTR-ToF-MS monitoring to explore, using VOCs as biomarkers, (i) the huge number of variables influencing AF in wine, and (ii) applications of single/mixed starter cultures in wine. Reported preliminary findings underlined the presence of different behaviors on grape juice and on must, respectively, and confirmed differences among the single yeast strains ‘volatomes’. It was one of the first studies to include the simultaneous inoculation on two non-Saccharomyces species together with a S. cerevisiae strain in terms of VOC contribution. Among the other outcomes, evidence suggests that the addition of M. pulcherrima to the coupled S. cerevisiae/T. delbrueckii can modify the global release of volatiles as a function of the characteristics of the fermented matrix.

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Harihastuti, Nani, Rame Rame, and Silvy Djayanti. "High Performance of Enzymatic Bioprocess for Production of Biomassed-based Bioethanol of Sago Palm Fiber Waste." Jurnal Riset Teknologi Pencegahan Pencemaran Industri 9, no. 2 (2018): 37–45. http://dx.doi.org/10.21771/jrtppi.2018.v9.no2.p37-45.

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Abstract:

Biomass waste in the form of fiber dregs contains many components of lignocellulose and hemicellulose. Lignocellulose can be used to produce ethanol through enzymatic biotechnology processes. Sago palm fiber industry is one potential industry producing biomass waste in the form of solid waste of fiber dregs (about 30% from the weight of processed raw materials). Solid fiber waste contains crude fiber and lignocellulose compound consists of cellulose (35-50%), hemicellulose ( 20-35%) and lignin (12-20%). This study aimed to utilize solid waste of sago palm fiber as a raw material of bioethanol production through enzymatic biotechnology processes of delignification, saccharification and fermentation which was then purified by distillation process to get ethanol. Delignification, saccharification, and fermentation stages are conducted using Phanerochaete chrysosporus Mushroom, Trichoderma viride fungus, and saccharomyces cerevisiae, respectively and then purified by distillation process (one level) to produce ethanol. The process of saccharification and fermentation process were done in an integrated manner (addition of Trichoderma viride and yeast saccharomyces cereviceae fungi done simultaneously). The weight of raw materials of solid waste fiber treated was about 6 kgs. Alcohol content obtained was about ± 4% (distillation). No water, air, and soil pollution inflicted, more added value, and sustainable were the main benefits of biotech process or bioprocess.

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Journal articles on the topic 'Yeast bioprocess'

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