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Journal articles on the topic 'Fermentation pathways'
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1
Akan, Madina, Andreas Gudiksen, Yasemin Baran, et al. "Exploring the Potential of Non-Conventional Yeasts in Wine Fermentation with a Focus on Saccharomycopsis fermentans." Fermentation 9, no. 9 (2023): 786. http://dx.doi.org/10.3390/fermentation9090786.
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Despite the increasing number of publications on non-conventional yeasts (NCYs), many areas in this field remain poorly understood, making the examination of these strains important for determining their potential in wine fermentations. The amino acid metabolic pathways involved, particularly the catabolic Ehrlich pathway but also anabolic pathways such as the leucine biosynthesis pathway, are crucial for producing high-value aroma compounds that contribute to the final flavour of wine. We examined the potential use of Saccharomycopsis fermentans in wine fermentations. We selected mutant strains resistant to the toxic compound trifluoro-leucine (TFL), verified mutations in the SfLEU4 gene, and characterized the ability of the resulting strains to contribute to fermentation bouquets. Resistance to TFL relieves feedback inhibition in the leucine biosynthesis pathway and resulted in increased leucine biosynthesis. Concomitantly, the S. fermentans TFL-resistant mutants generated increased amounts of isoamyl alcohol and isovalerate during wine fermentation. Selection of TFL-resistant strains thus provides a generally applicable strategy for the improvement in NCYs and their utilization in co-fermentation processes for different grape must varieties.
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Li, Shuai, Yueran Han, Ming Yan, Shuyi Qiu, and Jun Lu. "Machine Learning and Multi-Omics Integration to Reveal Biomarkers and Microbial Community Assembly Differences in Abnormal Stacking Fermentation of Sauce-Flavor Baijiu." Foods 14, no. 2 (2025): 245. https://doi.org/10.3390/foods14020245.
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Stacking fermentation is critical in sauce-flavor Baijiu production, but winter production often sees abnormal fermentations, like Waistline and Sub-Temp fermentation, affecting yield and quality. This study used three machine learning models (Logistic Regression, KNN, and Random Forest) combined with multi-omics (metagenomics and flavoromics) to develop a classification model for abnormal fermentation. SHAP analysis identified 13 Sub-Temp Fermentation and 9 Waistline microbial biomarkers, along with 9 Sub-Temp Fermentation and 12 Waistline flavor biomarkers. Komagataeibacter and Gluconacetobacter are key for normal fermentation, while Ligilactobacillus and Lactobacillus are critical in abnormal cases. Excessive acid and ester markers caused unbalanced aromas in abnormal fermentations. Additionally, ecological models reveal the bacterial community assembly in abnormal fermentations was influenced by stochastic factors, while the fungal community assembly was influenced by deterministic factors. RDA analysis shows that moisture significantly drove Sub-Temp fermentation. Differential gene analysis and KEGG pathway enrichment identify metabolic pathways for flavor markers. This study provides a theoretical basis for regulating stacking fermentation and ensuring Baijiu quality.
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Hallenbeck, P. C. "Fundamentals of the fermentative production of hydrogen." Water Science and Technology 52, no. 1-2 (2005): 21–29. http://dx.doi.org/10.2166/wst.2005.0494.
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The molecular details behind hydrogen evolution during fermentation are reviewed. Hydrogen is evolved by hydrogenase, a class of enzymes containing complex metallo-centers. In most cases, sugars are degraded to pyruvate which in turn is converted to a variety of fermentation products. Various pathways leading to fermentative hydrogen generation are outlined and discussed. Thermophilic fermentations have higher yields than mesophilic ones. Yields are thought to be limited to 4H2 per glucose under standard conditions. The highlights of some actual studies of fermentations are presented and ways of potentially increasing hydrogen yields are discussed. It may be possible to achieve higher hydrogen yields by carrying out fermentations under microaerobic conditions where limited respiration could provide additional reducing power to drive the nearly complete conversion of sugar substrates to hydrogen.
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Boll, Matthias, Johannes W. Kung, Ulrich Ermler, Berta M. Martins, and Wolfgang Buckel. "Fermentative Cyclohexane Carboxylate Formation in Syntrophus aciditrophicus." Journal of Molecular Microbiology and Biotechnology 26, no. 1-3 (2016): 165–79. http://dx.doi.org/10.1159/000440881.
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Short-chain fatty acids such as acetic, propionic, butyric or lactic acids are typical primary fermentation products in the anaerobic feeding chain. Fifteen years ago, a novel fermentation type was discovered in the obligately anaerobic Deltaproteobacterium <i>Syntrophus aciditrophicus</i>. During fermentative growth with crotonate and/or benzoate, acetate is formed in the oxidative branch and cyclohexane carboxylate in the reductive branch. In both cases cyclohexa-1,5-diene-1-carboxyl-CoA (Ch1,5CoA) is a central intermediate that is either formed by a class II benzoyl-CoA reductase (fermentation of benzoate) or by reverse reactions of the benzoyl-CoA degradation pathway (fermentation of crotonate). Here, we summarize the current knowledge of the enzymology involved in fermentations yielding cyclohexane carboxylate as an excreted product. The characteristic enzymes involved are two acyl-CoA dehydrogenases specifically acting on Ch1,5CoA and cyclohex-1-ene-1-carboxyl-CoA. Both enzymes are also employed during the syntrophic growth of <i>S. aciditrophicus</i> with cyclohexane carboxylate as the carbon source in coculture with a methanogen. An investigation of anabolic pathways in <i>S. aciditrophicus</i> revealed a rather unusual pathway for glutamate synthesis involving a <i>Re</i>-citrate synthase. Future work has to address the unresolved question concerning which components are involved in reoxidation of the NADH formed in the oxidative branch of the unique cyclohexane carboxylate fermentation pathway in <i>S. aciditrophicus</i>.
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Gil-Monreal, Miriam, Beatrice Giuntoli, Ana Zabalza, Francesco Licausi, and Mercedes Royuela. "ERF-VII transcription factors induce ethanol fermentation in response to amino acid biosynthesis-inhibiting herbicides." Journal of Experimental Botany 70, no. 20 (2019): 5839–51. http://dx.doi.org/10.1093/jxb/erz355.
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Abstract Herbicides inhibiting either aromatic or branched-chain amino acid biosynthesis trigger similar physiological responses in plants, despite their different mechanism of action. Both types of herbicides are known to activate ethanol fermentation by inducing the expression of fermentative genes; however, the mechanism of such transcriptional regulation has not been investigated so far. In plants exposed to low-oxygen conditions, ethanol fermentation is transcriptionally controlled by the ethylene response factors-VII (ERF-VIIs), whose stability is controlled in an oxygen-dependent manner by the Cys-Arg branch of the N-degron pathway. In this study, we investigated the role of ERF-VIIs in the regulation of the ethanol fermentation pathway in herbicide-treated Arabidopsis plants grown under aerobic conditions. Our results demonstrate that these transcriptional regulators are stabilized in response to herbicide treatment and are required for ethanol fermentation in these conditions. We also observed that mutants with reduced fermentative potential exhibit higher sensitivity to herbicide treatments, thus revealing the existence of a mechanism that mimics oxygen deprivation to activate metabolic pathways that enhance herbicide tolerance. We speculate that this signaling pathway may represent a potential target in agriculture to affect tolerance to herbicides that inhibit amino acid biosynthesis.
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Fan, Jinlin, Zheng Xiao, Wanwei Qiu, et al. "Analysis of Metabolic Components of JUNCAO Wine Based on GC-QTOF-MS." Foods 12, no. 11 (2023): 2254. http://dx.doi.org/10.3390/foods12112254.
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JUNCAO wine fermentation metabolites are closely related to the final quality of the product. Currently, there are no studies of dynamic metabolite changes during fermentation of JUNCAO wine. Here, we used gas chromatography quadrupole time-of-flight mass spectrometry (GC-QTOF-MS) metabolomics and multivariate statistical analysis to explore the relationship between metabolites and fermentation time. A total of 189 metabolites were annotated throughout the fermentation process. The principal component analysis (PCA) revealed a clear separation between the samples in the early and late stages of fermentation. A total of 60 metabolites were annotated as differential during the fermentation (variable importance in the projection, VIP > 1, and p < 0.05), including 21 organic acids, 10 amino acids, 15 sugars and sugar alcohols, and 14 other metabolites. Pathway analysis showed that the most commonly influenced pathways (impact value > 0.1 and p < 0.05) were tricarboxylic acid cycle, alanine, aspartic acid and glutamic acid metabolism, pyrimidine metabolism, and other 10 metabolic pathways. Moreover, integrated metabolic pathways are generated to understand the conversion and accumulation of differential metabolites. Overall, these results provide a comprehensive overview of metabolite changes during fermentation of JUNCAO wine.
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Evers, Marie Sarah, Chloé Roullier-Gall, Christophe Morge, et al. "Thiamine and Biotin: Relevance in the Production of Volatile and Non-Volatile Compounds during Saccharomyces cerevisiae Alcoholic Fermentation in Synthetic Grape Must." Foods 12, no. 5 (2023): 972. http://dx.doi.org/10.3390/foods12050972.
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Vitamins are major cofactors to numerous key metabolic pathways in enological yeasts, and both thiamine and biotin, notably, are believed to be essential to yeast fermentation and growth, respectively. In order to further assess and clarify their role in winemaking, and in the resulting wine, alcoholic fermentations of a commercial Saccharomyces cerevisiae active dried yeast were conducted in synthetic media containing various concentrations of both vitamins. Growth and fermentation kinetics were monitored and proved the essential character of biotin in yeast growth, and of thiamine in fermentation. The synthetic wine volatile compounds were quantified, and notable influences of both vitamins appeared, through a striking positive effect of thiamine on the production of higher alcohols, and of biotin on fatty acids. Beyond the evidence of this influence on fermentations and on the production of volatiles, this work proves, for the first time, the impact held by vitamins on wine yeasts’ exometabolome, investigated through an untargeted metabolomic analysis. This highlighted chemical differences in the composition of synthetic wines through a notably marked influence of thiamine on 46 named S. cerevisiae metabolic pathways, and especially in amino acid-associated metabolic pathways. This provides, overall, the first evidence of the impact held by both vitamins on the wine.
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Clark, David P. "The fermentation pathways ofEscherichia coli." FEMS Microbiology Letters 63, no. 3 (1989): 223–34. http://dx.doi.org/10.1111/j.1574-6968.1989.tb03398.x.
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Tian, Ping, Jiaqiong Wan, Tuo Yin, et al. "Acidity, sugar, and alcohol contents during the fermentation of Osmanthus-flavored sweet rice wine and microbial community dynamics." PeerJ 13 (January 30, 2025): e18826. https://doi.org/10.7717/peerj.18826.
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Sweet rice wine is a popular traditional Chinese rice wine widely loved by Chinese people for its high nutritional value. Osmanthus flower petals contain various nutrients and have good medicinal value. However, the dynamics of the sugar level, acidity, alcohol content, and microbial community during the fermentation of Osmanthus-flavored sweet rice wine have not been evaluated, which can lead to the unstable quality of Osmanthus flower sweet rice wine (OFSRW). In this study, the dynamic changes in sugar level, acidity, alcohol content, microbial community composition, and microbial metabolic pathways during traditional fermentation of OFSRW at four-time points—0 h (AG0), 24 h (AG24), 36 h (AG36), and 43 h (AG43)—were analyzed via direct titration, total acid assays, alcoholometry, and high-throughput macrogenomic techniques. First, we found that bacteria were the dominant microorganisms in the early stage of OFSRW fermentation (AG0), fungi were the dominant microorganisms in the middle and late stages of fermentation (AG24 and AG36), and Rhizopus was the main fungal genus throughout fermentation. Acidity and total sugars increased with fermentation time, and alcohol was not detected until the end of fermentation. Diversity analysis revealed that the dominant species at the beginning of natural fermentation was A. johnsonii, and R. delemar became the dominant species as natural fermentation progressed. Metabolic pathway analysis revealed that energy production and conversion, carbohydrate transport, amino acid transport, and metabolic pathways were the most active metabolic pathways in the fermenter. These results provide a reference basis for changes in the microbial community during the fermentation of cinnamon-flavored sweet rice wine.
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SACHDEVA TAGGAR, MONICA, AMANPREET KAUR, CHAHAK JAIN, ANU KALIA, and SARBJIT SINGH SOOCH. "HYDROGEN PRODUCTION VIA DARK FERMENTATION: A REVIEW OF INFLUENTIAL FACTORS." Cellulose Chemistry and Technology 58, no. 9-10 (2024): 1051–63. https://doi.org/10.35812/cellulosechemtechnol.2024.58.90.
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Biohydrogen is a promising low-carbon energy source due to its high energy density, and emerging technologies have been studied to achieve highly efficient and competitive H2 production. The biological hydrogen production involves microbe-assisted bioconversion, either in the presence or in the absence of light, called photo-fermentation or dark fermentation, respectively. Biohydrogen production using fermentative conversion of organic carbon in the absence of light, i.e., dark fermentation, has gained great interest during the last few decades. The mechanistic understanding of various metabolic pathways involved in dark fermentative hydrogen production is well understood and reviewed here. Further, the hydrogen yield is affected by a number of factors during the fermentation of organic substrates by either pure or mixed microbial cultures, and some of the pertinent factors have been discussed in this review. This review aims to present the current state of knowledge on the dark fermentation process, focusing on the use of waste materials as substrates.
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Wan, Jiaqiong, Ping Tian, Xiaozhen Liu, and Hanyao Zhang. "Analysis of the Changes in Physicochemical Properties and Microbial Communities During Fermentation of Sweet Fermented Rice." Foods 14, no. 7 (2025): 1121. https://doi.org/10.3390/foods14071121.
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As a traditional rice wine, sweet fermented rice (SFR) is widely loved because of its unique flavor and high nutritional value. However, the physicochemical properties, microbial community composition, and metabolic pathway changes during the fermentation process of sweet wine have not been evaluated, and these changes can lead to unstable SFR quality. In this study, we used high-throughput sequencing technology to analyze and elucidate the dynamic changes in the microbial community, metabolic pathways, and carbohydrate enzyme functions in traditional SFR fermentation broth. The results revealed that Rhizopus abundance = 160,943.659 and Wickerhamomyces abundance = 241,660.954 were the predominant fungal genera in the fermentation process from the beginning (A0) to the end (A43) of SFR fermentation. The results of the diversity analysis revealed that the structure and composition of the microbial communities first increased but then decreased. Metabolic pathway analysis showed that energy production and conversion, carbohydrate transport, and amino acid transport were the most active metabolic pathways in fermentation. Moreover, the three primary functions of glycosyltransferases (GTs), glycoside hydrolases (GHs), and carbohydrate-binding modules (CBMs) in carbohydrate enzyme analysis were involved in the whole fermentation process. This study only provides some insight into the dynamic changes in the microbial population of SFR single samples prepared under fixed conditions. It provides a reference for optimizing the physicochemical properties of SFR fermentation broth, controlling the microbial community structure, optimizing fermentation conditions, and improving product quality.
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Zigha, Assia, Eric Rosenfeld, Philippe Schmitt, and Catherine Duport. "The Redox Regulator Fnr Is Required for Fermentative Growth and Enterotoxin Synthesis in Bacillus cereus F4430/73." Journal of Bacteriology 189, no. 7 (2007): 2813–24. http://dx.doi.org/10.1128/jb.01701-06.
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ABSTRACT Glucose-grown cells of Bacillus cereus respond to anaerobiosis and low extracellular oxidoreduction potentials (ORP), notably by enhancing enterotoxin production. This response involves the ResDE two-component system. We searched the B. cereus genome for other redox response regulators potentially involved in this adaptive process, and we identified one gene encoding a protein predicted to have an amino acid sequence 58% identical (80% similar) to that of the Bacillus subtilis Fnr redox regulator. The fnr gene of the food-borne pathogen B. cereus F4430/73 has been cloned and partially characterized. We showed that fnr was up-regulated during anaerobic fermentation, especially when fermentation occurred at low ORP (under highly reducing conditions). The expression of fnr was down-regulated in the presence of O2 and nitrate which, unlike fumarate, stimulated the respiratory pathways. The inactivation of B. cereus fnr abolished fermentative growth but only moderately affected aerobic and anaerobic nitrate respiratory growth. Analyses of glucose by-products and the transcription profiles of key catabolic genes confirmed the strong regulatory impact of Fnr on B. cereus fermentative pathways. More importantly, the fnr mutation strongly decreased the expression of PlcR-dependent hbl and nhe genes, leading to the absence of hemolysin BL (Hbl) and nonhemolytic enterotoxin (Nhe) secretion by the mutant. These data indicate that fnr is essential for both fermentation and toxinogenesis. The results also suggest that both Fnr and the ResDE two-component system belong to a redox regulatory pathway that functions at least partially independently of the pleiotropic virulence gene regulator PlcR to regulate enterotoxin gene expression.
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Santos, Mayara Vieira, Adriana Régia Marques Souza, Maria Carolina Santos Silva, and Gabriel Luis Castiglioni. "Population dynamics of Saccharomyces cerevisiae PE-2 and CAT-1 in CO-culture for the production of ethanol." Acta Scientiarum. Technology 42 (May 28, 2020): e43427. http://dx.doi.org/10.4025/actascitechnol.v42i1.43427.
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In the Brazilian industries, the inoculum used throughout the harvest of ethanol production consists of a combination of two or more yeast strains. The combination of yeasts may influence in the metabolic pathways of microorganisms and increase the yields and production rates of some compounds. In biotechnological processes with co-culture, one microorganism can prevail over the other. Therefore, the knowledge about how the population dynamics occurs during fermentation allows modifications in the process in order to obtain higher yields and to achieve greater fermentative efficiency. The aim of this study was to investigate the fermentation with synthetic sugar cane broth in co-culture of Saccharomyces cerevisiae strains CAT-1 and PE-2 followed by molecular fermentation monitoring. The concentration of biomass, ethanol, glycerol, acetic acid and residual sucrose were monitored to verify the influence of different combinations during the fermentation. The mixture of CAT-1 and PE-2 presented the highest ethanol production, with higher performance of fermentative parameters than pure cultures
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Salmon, Jean-Michel, and Pierre Barre. "Improvement of Nitrogen Assimilation and Fermentation Kinetics under Enological Conditions by Derepression of Alternative Nitrogen-Assimilatory Pathways in an Industrial Saccharomyces cerevisiae Strain." Applied and Environmental Microbiology 64, no. 10 (1998): 3831–37. http://dx.doi.org/10.1128/aem.64.10.3831-3837.1998.
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ABSTRACT Metabolism of nitrogen compounds by yeasts affects the efficiency of wine fermentation. Ammonium ions, normally present in grape musts, reduce catabolic enzyme levels and transport activities for nonpreferred nitrogen sources. This nitrogen catabolite repression severely impairs the utilization of proline and arginine, both common nitrogen sources in grape juice that require the proline utilization pathway for their assimilation. We attempted to improve fermentation performance by genetic alteration of the regulation of nitrogen-assimilatory pathways in Saccharomyces cerevisiae. One mutant carrying a recessive allele ofure2 was isolated from an industrial S. cerevisiae strain. This mutation strongly deregulated the proline utilization pathway. Fermentation kinetics of this mutant were studied under enological conditions on simulated standard grape juices with various nitrogen levels. Mutant strains produced more biomass and exhibited a higher maximum CO2 production rate than the wild type. These differences were primarily due to the derepression of amino acid utilization pathways. When low amounts of dissolved oxygen were added, the mutants could assimilate proline. Biomass yield and fermentation rate were consequently increased, and the duration of the fermentation was substantially shortened. S. cerevisiae strains lacking URE2 function could improve alcoholic fermentation of natural media where proline and other poorly assimilated amino acids are the major potential nitrogen source, as is the case for most fruit juices and grape musts.
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Boban, Ana, Urska Vrhovsek, Andrea Anesi, et al. "Modulation of Aromatic Amino Acid Metabolism by Indigenous Non-Saccharomyces Yeasts in Croatian Maraština Wines." Foods 13, no. 18 (2024): 2939. http://dx.doi.org/10.3390/foods13182939.
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This study aimed to provide novel information on the impact of indigenous non-Saccharomyces yeasts, including Metschnikowia chrysoperlae, Metschnikowia sinensis/shanxiensis, Metschnikowia pulcherrima, Lachancea thermotolerans, Hanseniaspora uvarum, Hanseniaspora guilliermondii, and Pichia kluyveri, on metabolites related to the metabolism of tryptophan, phenylalanine, and tyrosine. The experiment included two fermentation practices: monoculture and sequential fermentation with commercial Saccharomyces cerevisiae, using sterile Maraština grape juice. A targeted approach through ultrahigh-resolution liquid chromatography associated with mass spectrometry was used to quantify 38 metabolites. All the indigenous yeasts demonstrated better consumption of tryptophan in monoculture than in interaction with S. cerevisiae. M. sinensis/shanxiensis was the only producer of indole-3-carboxylic acid, while its ethyl ester was detected in monoculture fermentation with H. guilliermondii. H. guilliermondii consumed the most phenylalanine among the other isolates. 5-hydroxy-L-tryptophan was detected in fermentations with M. pulcherrima and M. sinensis/shanxiensis. M. pulcherrima significantly increased tryptophol content and utilised tyrosine in monoculture fermentations. Sequential fermentation with M. sinensis/shanxiensis and S. cerevisiae produced higher amounts of N-acetyl derivatives of tryptophan and phenylalanine, while H. guilliermondii-S. cerevisiae fermentation resulted in wines with the highest concentrations of L-kynurenine and 3-hydroxyanthranilic acid. P. kluyveri produced the highest concentration of N-acetyl-L-tyrosine in monoculture fermentations. These findings highlight the different yeast metabolic pathways.
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Pérez-Torrado, Roberto, Jose M. Bruno-Bárcena, and Emilia Matallana. "Monitoring Stress-Related Genes during the Process of Biomass Propagation of Saccharomyces cerevisiae Strains Used for Wine Making." Applied and Environmental Microbiology 71, no. 11 (2005): 6831–37. http://dx.doi.org/10.1128/aem.71.11.6831-6837.2005.
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ABSTRACT Physiological capabilities and fermentation performance of Saccharomyces cerevisiae strains to be employed during industrial wine fermentations are critical for the quality of the final product. During the process of biomass propagation, yeast cells are dynamically exposed to a mixed and interrelated group of known stresses such as osmotic, oxidative, thermic, and/or starvation. These stressing conditions can dramatically affect the parameters of the fermentation process and the technological abilities of the yeast, e.g., the biomass yield and its fermentative capacity. Although a good knowledge exists of the behavior of S. cerevisiae under laboratory conditions, insufficient knowledge is available about yeast stress responses under the specific media and growth conditions during industrial processes. We performed growth experiments using bench-top fermentors and employed a molecular marker approach (changes in expression levels of five stress-related genes) to investigate how the cells respond to environmental changes during the process of yeast biomass production. The data show that in addition to the general stress response pathway, using the HSP12 gene as a marker, other specific stress response pathways were induced, as indicated by the changes detected in the mRNA levels of two stress-related genes, GPD1 and TRX2. These results suggest that the cells were affected by osmotic and oxidative stresses, demonstrating that these are the major causes of the stress response throughout the process of wine yeast biomass production.
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Mendes-Ferreira, A., M. del Olmo, J. García-Martínez, et al. "Transcriptional Response of Saccharomyces cerevisiae to Different Nitrogen Concentrations during Alcoholic Fermentation." Applied and Environmental Microbiology 73, no. 9 (2007): 3049–60. http://dx.doi.org/10.1128/aem.02754-06.
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ABSTRACT Gene expression profiles of a wine strain of Saccharomyces cerevisiae PYCC4072 were monitored during alcoholic fermentations with three different nitrogen supplies: (i) control fermentation (with enough nitrogen to complete sugar fermentation), (ii) nitrogen-limiting fermentation, and (iii) the addition of nitrogen to the nitrogen-limiting fermentation (refed fermentation). Approximately 70% of the yeast transcriptome was altered in at least one of the fermentation stages studied, revealing the continuous adjustment of yeast cells to stressful conditions. Nitrogen concentration had a decisive effect on gene expression during fermentation. The largest changes in transcription profiles were observed when the early time points of the N-limiting and control fermentations were compared. Despite the high levels of glucose present in the media, the early responses of yeast cells to low nitrogen were characterized by the induction of genes involved in oxidative glucose metabolism, including a significant number of mitochondrial associated genes resembling the yeast cell response to glucose starvation. As the N-limiting fermentation progressed, a general downregulation of genes associated with catabolism was observed. Surprisingly, genes encoding ribosomal proteins and involved in ribosome biogenesis showed a slight increase during N starvation; besides, genes that comprise the RiBi regulon behaved distinctively under the different experimental conditions. Here, for the first time, the global response of nitrogen-depleted cells to nitrogen addition under enological conditions is described. An important gene expression reprogramming occurred after nitrogen addition; this reprogramming affected genes involved in glycolysis, thiamine metabolism, and energy pathways, which enabled the yeast strain to overcome the previous nitrogen starvation stress and restart alcoholic fermentation.
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Jiang, Jiashun, Jingan Yang, Tong Zhu, Yongjin Hu, Hong Li, and Lijing Liu. "Research on the Quality Variation Patterns During the Fermentation Process of Coffee-Grounds Craft Beer." Foods 14, no. 6 (2025): 1014. https://doi.org/10.3390/foods14061014.
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To investigate the metabolic differences and mechanisms during the fermentation process of coffee-grounds craft beer, HS-SPME-GC/MS untargeted metabolomics technology was used to study the metabolic differences during the fermentation process of coffee-grounds craft beer. Multivariate statistical analysis and pathway analysis were combined to screen for significantly different metabolites with variable weight values of VIP ≥ 1 and p < 0.05. The results indicate that at time points T7, T14, T21, and T28, a total of 183 differential metabolites were detected during the four fermentation days, with 86 metabolites showing significant differences. Its content composition is mainly composed of lipids and lipid-like molecules, organic oxygen compounds, and benzoids, accounting for 63.64% of the total differential metabolites. KEGG enrichment analysis of differentially expressed metabolites showed a total of 35 metabolic pathways. The top 20 metabolic pathways were screened based on the corrected p-value, and the significantly differentially expressed metabolites were mainly enriched in pathways such as protein digestion and absorption, glycosaminoglycan biosynthesis heparan sulfate/heparin, and benzoxazinoid biosynthesis. The different metabolic mechanisms during the fermentation process of coffee-grounds craft beer reveal the quality changes during the fermentation process, providing theoretical basis for improving the quality of coffee-grounds craft beer and having important theoretical and practical significance for improving the quality evaluation system of coffee-grounds craft beer.
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CLARK, D. "The fermentation pathways of Escherichia coli." FEMS Microbiology Reviews 63, no. 3 (1989): 223–34. http://dx.doi.org/10.1016/0168-6445(89)90033-8.
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Zhang, X., K. Jantama, K. T. Shanmugam, and L. O. Ingram. "Reengineering Escherichia coli for Succinate Production in Mineral Salts Medium." Applied and Environmental Microbiology 75, no. 24 (2009): 7807–13. http://dx.doi.org/10.1128/aem.01758-09.
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ABSTRACT The fermentative metabolism of glucose was redirected to succinate as the primary product without mutating any genes encoding the native mixed-acid fermentation pathway or redox reactions. Two changes in peripheral pathways were together found to increase succinate yield fivefold: (i) increased expression of phosphoenolpyruvate carboxykinase and (ii) inactivation of the glucose phosphoenolpyruvate-dependent phosphotransferase system. These two changes increased net ATP production, increased the pool of phosphoenolpyruvate available for carboxylation, and increased succinate production. Modest further improvements in succinate yield were made by inactivating the pflB gene, encoding pyruvate formate lyase, resulting in an E scherichia coli pathway that is functionally similar to the native pathway in Actinobacillus succinogenes and other succinate-producing rumen bacteria.
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Rosenfeld, Eric, Bertrand Beauvoit, Bruno Blondin, and Jean-Michel Salmon. "Oxygen Consumption by Anaerobic Saccharomyces cerevisiae under Enological Conditions: Effect on Fermentation Kinetics." Applied and Environmental Microbiology 69, no. 1 (2003): 113–21. http://dx.doi.org/10.1128/aem.69.1.113-121.2003.
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ABSTRACT The anaerobic growth of the yeast Saccharomyces cerevisiae normally requires the addition of molecular oxygen, which is used to synthesize sterols and unsaturated fatty acids (UFAs). A single oxygen pulse can stimulate enological fermentation, but the biochemical pathways involved in this phenomenon remain to be elucidated. We showed that the addition of oxygen (0.3 to 1.5 mg/g [dry mass] of yeast) to a lipid-depleted medium mainly resulted in the synthesis of the sterols and UFAs required for cell growth. However, the addition of oxygen during the stationary phase in a medium containing excess ergosterol and oleic acid increased the specific fermentation rate, increased cell viability, and shortened the fermentation period. Neither the respiratory chain nor de novo protein synthesis was required for these medium- and long-term effects. As de novo lipid synthesis may be involved in ethanol tolerance, we studied the effect of oxygen addition on sterol and UFA auxotrophs (erg1 and ole1 mutants, respectively). Both mutants exhibited normal anaerobic fermentation kinetics. However, only the ole1 mutant strain responded to the oxygen pulse during the stationary phase, suggesting that de novo sterol synthesis is required for the oxygen-induced increase of the specific fermentation rate. In conclusion, the sterol pathway appears to contribute significantly to the oxygen consumption capacities of cells under anaerobic conditions. Nevertheless, we demonstrated the existence of alternative oxygen consumption pathways that are neither linked to the respiratory chain nor linked to heme, sterol, or UFA synthesis. These pathways dissipate the oxygen added during the stationary phase, without affecting the fermentation kinetics.
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Wang, Yubao, Bingjun Lin, and Zhengxu Li. "Effect of Lactobacillus plantarum Fermentation on Metabolites in Lotus Leaf Based on Ultra-High-Performance Liquid Chromatography–High-Resolution Mass Spectrometry." Fermentation 8, no. 11 (2022): 599. http://dx.doi.org/10.3390/fermentation8110599.
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The lotus leaf is a raw material commonly used in slimming herbal products, but the deep processing technology is insufficient. Lactic acid bacteria (LAB) fermentation is an effective method to improve the efficacy of plant materials. In this study, ultra-high-performance liquid chromatography–high-resolution mass spectrometry (UHPLC–HR-MS) was used to explore the differential metabolites of a lotus leaf aqueous extract before and after fermentation. Information about the metabolites in the water extract of lotus leaves before and after fermentation was collected in positive- and negative-ion modes, and the metabolites identified before and after fermentation were screened by multivariate statistical analysis. A total of 91 different metabolites were obtained. They included flavonoids, alkaloids, phenylpropanoids, organic acids and derivatives, terpenoids, fatty acids and fatty acyls, phenols, amino acid derivatives and others. Compared with the metabolites’ levels before fermentation, the relative contents of 68 metabolites were upregulated after fermentation, and the relative contents of 23 metabolites were downregulated. A Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis identified 25 metabolic pathways, of which flavone and flavonol biosynthesis, citrate cycle and flavonoid biosynthesis were the main metabolic pathways. The results of this study can provide a basis for further research and the development of products containing lotus leaves fermented by LAB.
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Aslankoohi, Elham, Bo Zhu, Mohammad Naser Rezaei, et al. "Dynamics of the Saccharomyces cerevisiae Transcriptome during Bread Dough Fermentation." Applied and Environmental Microbiology 79, no. 23 (2013): 7325–33. http://dx.doi.org/10.1128/aem.02649-13.
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ABSTRACTThe behavior of yeast cells during industrial processes such as the production of beer, wine, and bioethanol has been extensively studied. In contrast, our knowledge about yeast physiology during solid-state processes, such as bread dough, cheese, or cocoa fermentation, remains limited. We investigated changes in the transcriptomes of three genetically distinctSaccharomyces cerevisiaestrains during bread dough fermentation. Our results show that regardless of the genetic background, all three strains exhibit similar changes in expression patterns. At the onset of fermentation, expression of glucose-regulated genes changes dramatically, and the osmotic stress response is activated. The middle fermentation phase is characterized by the induction of genes involved in amino acid metabolism. Finally, at the latest time point, cells suffer from nutrient depletion and activate pathways associated with starvation and stress responses. Further analysis shows that genes regulated by the high-osmolarity glycerol (HOG) pathway, the major pathway involved in the response to osmotic stress and glycerol homeostasis, are among the most differentially expressed genes at the onset of fermentation. More importantly, deletion ofHOG1and other genes of this pathway significantly reduces the fermentation capacity. Together, our results demonstrate that cells embedded in a solid matrix such as bread dough suffer severe osmotic stress and that a proper induction of the HOG pathway is critical for optimal fermentation.
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Zhou, Yunhan. "Research Progress on the Mechanism of Action and Screening of Acid-lowering Yeast in Wine." Highlights in Science, Engineering and Technology 109 (July 24, 2024): 274–81. http://dx.doi.org/10.54097/5hsfs222.
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The acidity of wine is a crucial factor affecting its quality and stability, serving as an important index for wine evaluation. The paper reviewed the application of acid-lowering yeast pathways and screening methods in wine, kiwi wine, and milone. As a biological acid-lowering method, acid-lowering yeast primarily relies on the lactose-lactate fermentation pathway and the malate-lactic acid fermentation route to reduce acidity. The method of acid reduction varies among the three types of beverages. Additionally, the paper explored the screening pathways for acid-lowering yeast. Beyond traditional screening methods, molecular biology techniques, gene editing techniques and adaptive evolution have further improved the screening efficiency and accuracy. By analyzing the fermentation conditions of different alcoholic beverages, different screening methods can be employed to improve the fermentation effect of acid reduction. Acid-lowering yeast has broad application prospects in the alcohol industry. Combined with gene technology to further study and innovate the yeast acid-lowering way, apply it to more alcohol, and promote the development and progress of the industry.
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Zailani, Nurliyana Sofiya, and Azila Adnan. "SUBSTRATES AND METABOLIC PATHWAYS IN SYMBIOTIC CULTURE OF BACTERIA AND YEAST (SCOBY) FERMENTATION: A MINI REVIEW." Jurnal Teknologi 84, no. 5 (2022): 155–65. http://dx.doi.org/10.11113/jurnalteknologi.v84.18534.
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Kombucha is a fermented beverage that is prepared traditionally by fermenting Symbiotic Culture of Bacteria and Yeast (SCOBY) with sugar and black/green tea, which is known as Camellia sinensis leaves. The previous study analyses the microbial composition that can be obtained in Kombucha production. Study shows that yeast species and acetic acid bacteria (AAB) species are the microorganisms that involve in the fermentation process of Kombucha. Some studies emphasize the chemical composition that was obtained from the production of Kombucha drinks such as organic acids, sugars, ethanol, and polyphenols. However, further review and elucidation regarding the substrates used and metabolic activity in Kombucha fermentation is necessary. Thus, the objective of this study is to review the metabolic pathway and substrates involve in Symbiotic Culture of Bacteria and Yeast (SCOBY) fermentation. This review also collected information related to the symbiosis of fermentation by yeast and AAB pathway in Kombucha fermentation. Several pharmaceutical effects of Kombucha were also discussed to prove the health benefits of Kombucha. To produce good quality and high yield of Kombucha that can provide various health benefits to consumers, it is crucial to understand the connection between the metabolic activity with Symbiotic Culture of Bacteria and Yeast (SCOBY) during the fermentation process of Kombucha. By conducting this review work, it could provide an insightful overview and better understanding of metabolic pathways and substrates involved in SCOBY and Kombucha fermentation.
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Park, Min Kyung, and Young-Suk Kim. "Distinctive Formation of Volatile Compounds in Fermented Rice Inoculated by Different Molds, Yeasts, and Lactic Acid Bacteria." Molecules 24, no. 11 (2019): 2123. http://dx.doi.org/10.3390/molecules24112123.
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Rice has been fermented to enhance its application in some foods. Although various microbes are involved in rice fermentation, their roles in the formation of volatile compounds, which are important to the characteristics of fermented rice, are not clear. In this study, diverse approaches, such as partial least squares-discriminant analysis (PLS-DA), metabolic pathway-based volatile compound formations, and correlation analysis between volatile compounds and microbes were applied to compare metabolic characteristics according to each microbe and determine microbe-specific metabolites in fermented rice inoculated by molds, yeasts, and lactic acid bacteria. Metabolic changes were relatively more activated in fermented rice inoculated by molds compared to other microbes. Volatile compound profiles were significantly changed depending on each microbe as well as the group of microbes. Regarding some metabolic pathways, such as carbohydrates, amino acids, and fatty acids, it could be observed that certain formation pathways of volatile compounds were closely linked with the type of microbes. Also, some volatile compounds were strongly correlated to specific microbes; for example, branched-chain volatiles were closely link to Aspergillus oryzae, while Lactobacillus plantarum had strong relationship with acetic acid in fermented rice. This study can provide an insight into the effects of fermentative microbes on the formation of volatile compounds in rice fermentation.
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Ojo, Abidemi Oluranti, and Olga de Smidt. "Lactic Acid: A Comprehensive Review of Production to Purification." Processes 11, no. 3 (2023): 688. http://dx.doi.org/10.3390/pr11030688.
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Lactic acid (LA) has broad applications in the food, chemical, pharmaceutical, and cosmetics industries. LA production demand rises due to the increasing demand for polylactic acid since LA is a precursor for polylactic acid production. Fermentative LA production using renewable resources, such as lignocellulosic materials, reduces greenhouse gas emissions and offers a cheaper alternative feedstock than refined sugars. Suitable pretreatment methods must be selected to minimize LA cost production, as the successful hydrolysis of lignocellulose results in sugar-rich feedstocks for fermentation. This review broadly focused on fermentative LA production from lignocellulose. Aspects discussed include (i). low-cost materials for fermentative LA production, (ii). pretreatment methods, (iii). enzymatic hydrolysis of cellulose and hemicellulose, (iv). lactic acid-producing microorganisms, including fungi, bacteria, genetically modified microorganisms, and their fermentative pathways, and (v). fermentation modes and methods. Industrial fermentative lactic acid production and purification, difficulties in using lignocellulose in fermentative LA production, and possible strategies to circumvent the challenges were discussed. A promising option for the industrial production and purification of LA that contains enzyme and cell recycling continuous simultaneous saccharification and fermentation coupled with membrane-based separation was proposed. This proposed system can eliminate substrate-, feedback-, and end-product inhibition, thereby increasing LA concentration, productivity, and yield.
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Zhao, Yao, Ruoqing Liu, Ying Mu, et al. "Study on the Mechanisms of Flavor Compound Changes During the Lactic Fermentation Process of Peach and Apricot Mixed Juice." Foods 13, no. 23 (2024): 3835. http://dx.doi.org/10.3390/foods13233835.
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This study employed headspace solid-phase microextraction gas chromatography–mass spectrometry (HS-SPME-GC-MS) and liquid chromatography–mass spectrometry (LC-MS) for non-targeted metabolomics analyses to examine the impact of mixed fermentation with various lactic acid bacteria (LAB) on the flavor compounds and metabolites of peach and apricot mixed juice (PAMJ), specifically focusing on the alterations of volatile compounds and non-volatile metabolites, as well as their metabolic pathways during the fermentation process. A total of 185 volatiles were identified using HS-SPME-GC-MS analysis, revealing significant differential metabolites, including eugenol, benzaldehyde, and γ-decalactone etc. The results indicated that lactic fermentation significantly enhanced the overall flavor of the juice toward the end of the fermentation process. In the interim, untargeted metabolomics utilizing LC-MS identified 1846 divergent metabolites, with 564 exhibiting up-regulation and 1282 demonstrating down-regulation. The metabolic pathway study performed by the Kyoto Encyclopedia of Genes and Genomes (KEGG) revealed significant changes in the metabolic levels of amino acids and saccharides after the lactic fermentation of PAMJ. Primarily associated with amino acid metabolism and starch and sucrose metabolism pathways. This work establishes a theoretical foundation for advancing fermented fruit juices with superior quality.
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Dal Bello, Fabio, Jens Walter, Stefan Roos, Hans Jonsson, and Christian Hertel. "Inducible Gene Expression in Lactobacillus reuteri LTH5531 during Type II Sourdough Fermentation." Applied and Environmental Microbiology 71, no. 10 (2005): 5873–78. http://dx.doi.org/10.1128/aem.71.10.5873-5878.2005.
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ABSTRACT Lactobacillus reuteri LTH5531 is a dominant member of the microbiota of type II sourdough fermentations. To investigate the genetic background of the ecological performance of LTH5531, in vivo expression technology was used to identify promoters that show elevated levels of expression during growth of this organism in a type II sourdough fermentation. Thirty-eight sourdough-induced fusions were detected, and 29 genes could be identified on the basis of the available sequence information. Four genes encoded stress-related functions (e.g., acid and general stress response), reflecting the harsh conditions prevailing during sourdough fermentation. Further, eight genes were involved in acquisition and synthesis of amino acids and nucleotides, indicating their limited availability in sourdough. The remaining genes were either part of functionally unrelated pathways or encoded hypothetical proteins. The identification of a putative proteinase and a component of the arginine deiminase pathway is of technological interest, as they are potentially involved in the formation of aroma precursors. Our study allowed insight into the transcriptional response of Lactobacillus reuteri to the dough environment, which establishes the molecular basis to investigate bacterial properties that are likely to contribute to the ecological performance of the organism and influence the final outcome of the fermentation.
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Kang, Tae Sun, Darren R. Korber, and Takuji Tanaka. "Regulation of Dual Glycolytic Pathways for Fructose Metabolism in Heterofermentative Lactobacillus panis PM1." Applied and Environmental Microbiology 79, no. 24 (2013): 7818–26. http://dx.doi.org/10.1128/aem.02377-13.
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ABSTRACTLactobacillus panisPM1 belongs to the group III heterofermentative lactobacilli that use the 6-phosphogluconate/phosphoketolase (6-PG/PK) pathway as their central metabolic pathway and are reportedly unable to grow on fructose as a sole carbon source. We isolated a variant PM1 strain capable of sporadic growth on fructose medium and observed its distinctive characteristics of fructose metabolism. The end product pattern was different from what is expected in typical group III lactobacilli using the 6-PG/PK pathway (i.e., more lactate, less acetate, and no mannitol). In addition,in silicoanalysis revealed the presence of genes encoding most of critical enzymes in the Embden-Meyerhof (EM) pathway. These observations indicated that fructose was metabolized via two pathways. Fructose metabolism in the PM1 strain was influenced by the activities of two enzymes, triosephosphate isomerase (TPI) and glucose 6-phosphate isomerase (PGI). A lack of TPI resulted in the intracellular accumulation of dihydroxyacetone phosphate (DHAP) in PM1, the toxicity of which caused early growth cessation during fructose fermentation. The activity of PGI was enhanced by the presence of glyceraldehyde 3-phosphate (GAP), which allowed additional fructose to enter into the 6-PG/PK pathway to avoid toxicity by DHAP. Exogenous TPI gene expression shifted fructose metabolism from heterolactic to homolactic fermentation, indicating that TPI enabled the PM1 strain to mainly use the EM pathway for fructose fermentation. These findings clearly demonstrate that the balance in the accumulation of GAP and DHAP determines the fate of fructose metabolism and the activity of TPI plays a critical role during fructose fermentation via the EM pathway inL. panisPM1.
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Demeyer, D., F. Piattoni, L. Mbanzamihigo, I. Immig, and L. Nollet. "Alternative hydrogen sink pathways in hindgut fermentation." Reproduction Nutrition Development 37, Suppl. 1 (1997): 67–68. http://dx.doi.org/10.1051/rnd:19970750.
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Wang, Haoming, Ting Wang, Jinghan Wang, et al. "Exploring the Potential Lipid-Lowering and Weight-Reducing Mechanisms of FH06 Fermented Beverages Based on Non-Targeted Metabolomics and Network Pharmacology." Fermentation 10, no. 6 (2024): 294. http://dx.doi.org/10.3390/fermentation10060294.
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Investigating the intricate pathways through which FH06 fermentation broth exerts lipid-lowering and weight-loss effects is pivotal for advancing our comprehension of metabolic regulation and therapeutic interventions. Ultrahigh-performance liquid chromatography quadrupole electrostatic field orbit trap mass spectrometry (UHPLC-QE-MS) detection and the ChEMBL database were used to determine the effective compounds in the FH06 fermentation broth and predict their targets. The TTD database and DisGeNET database were used to query obesity-related targets. The STRING database was used to construct protein interaction information. The Gene Ontology (GO) database and the Kyoto Encyclopedia of Genes and Genomes (KEGG) database were used to perform biological function annotation (GO) and KEGG pathway enrichment analyses of the targets. Results: A total of 85 effective compounds were screened from the fermentation broth of FH06; these compounds may act on TP53, PPARG, TNF, and other targets through 10 signaling pathways, such as the chemical carcinogenesis-receptor activation and lipid and atherosclerosis pathways, and exert pharmacological effects, such as hypoglycemic effects and weight loss. They also have anti-inflammatory, antioxidant, antitumor, and immunoregulatory effects. These findings reveal the active ingredients of FH06 fermentation broth and its multi-target and multi-channel characteristics in lipid lowering and weight loss. This study has positive implications for the clinical treatment of obesity using FH06, providing a theoretical and scientific basis for further developing of FH06-assisted lipid-lowering products.
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Bai, Chunyan, Boyuan Fan, Jinmei Hao, et al. "Changes in Microbial Community Diversity and the Formation Mechanism of Flavor Metabolites in Industrial-Scale Spontaneous Fermentation of Cabernet Sauvignon Wines." Foods 14, no. 2 (2025): 235. https://doi.org/10.3390/foods14020235.
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The key flavor compound formation pathways resulting from indigenous microorganisms during the spontaneous fermentation of wine have not been thoroughly described. In this study, high-throughput metagenomic sequencing and untargeted metabolomics were utilized to investigate the evolution of microbial and metabolite profiles during spontaneous fermentation in industrial-scale wine production and to elucidate the formation mechanisms of key flavor compounds. Metabolome analysis showed that the total amount of esters, fatty acids, organic acids, aldehydes, terpenes, flavonoids, and non-flavonoids increased gradually during fermentation. Enrichment analysis indicated that metabolic pathways related to the synthesis, decomposition, transformation, and utilization of sugars, amino acids, and fatty acids were involved in the formation of key flavor compounds in wine. Metagenomic analysis revealed that Saccharomyces, Hanseniaspora, Zygosaccharomyces, Wickerhamiella, Lactobacillus, and Fructobacillus were the dominant taxa during spontaneous fermentation. They were significantly positively correlated with organic acids, fatty acids, esters, phenols, aldehydes, terpenes, and phenols. In conclusion, this research provides new insights into the metabolic pathways of key flavor compounds formed by indigenous microorganisms during wine fermentation.
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Abdullah, Noradilin, Rosli Md Illias, Low Kheng Oon, Nardiah Rizwana Jaafar, Norhamiza Mohamad Sukri, and Roshanida Abdul Rahman. "METABOLIC PATHWAY MODIFICATION FOR PRODUCTION OF XYLITOL FROM GLUCOSE IN ESCHERICHIA COLI." Jurnal Teknologi 84, no. 3 (2022): 151–62. http://dx.doi.org/10.11113/jurnalteknologi.v84.18228.
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Glucose is a cheap and readily available substrate for production of large-scale chemicals. Synthesis of xylitol, a high demand chemical in global market is currently done by using xylose, which contributes to its high operational cost. Studies on production of xylitol from glucose have explored several approaches, from sequential fermentation to multiple and single gene expression. Xylitol-5-phosphate dehydrogenase (XPDH), is an enzyme that enables conversion of glucose to xylitol in a single step fermentation. This study explores conversion of xylitol from glucose in E. coli by the expression of xpdh from Clostridium difficile with modifications in metabolic pathways to enhance xylitol production. The xpdh gene was carried by pACYC-Duet-1 expression vector and induced by the addition of IPTG. Initial screening of E. coli expressing xpdh (NA116) was done by shake-flask fermentation for 24 hours and its metabolites were analyzed by HPLC. NA116 was able to produce 0.273 g/L xylitol from 4.33 g/L consumed glucose in 24 hours. Further metabolic pathway modification to eliminate competing pathways yielded four mutants, NA207 (∆rpiA), NA208 (∆rpiB), NA209 (∆pgi) and NA211 (∆rpi∆Apgi). Screening of mutants for xylitol production showed that highest xylitol production from glucose was achieved by NA211 with almost double the amount of the original strain, 0.585 g/L. This showed successful xylitol conversion from glucose in a single fermentation in E. coli with improved yield through metabolic pathway modification.
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Domińska, Marlena, Martyna Gloc, Magdalena Olak-Kucharczyk, and Katarzyna Paździor. "Dark Fermentation of Sizing Process Waste: A Sustainable Solution for Hydrogen Production and Industrial Waste Management." Water 17, no. 11 (2025): 1716. https://doi.org/10.3390/w17111716.
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The possibility of hydrogen (H2) production from sizing waste, specifically starch-based substrates, was investigated through dark fermentation. Modified starch substrates produced less (up to 54% without heating and 18% after heating) H2 than natural ones. However, heating modified starch samples led to 18% higher H2 production than unheated ones, suggesting that high temperatures activate more favorable metabolic pathways. The highest H2 production (215 mL/gTVS_substrate) was observed with unheated natural starch, where the classic butyric–acetic fermentation pathway predominated. This variant also generated the highest CO2 levels (250 mL/gTVS_substrate), confirming the correlation between H2 and CO2 production in these pathways. Modified starch substrates shifted fermentation towards fatty acid chain elongation, reducing CO2 production. The proportion of CO2 in the fermentation gases correlated strongly with H2 production across all variants. A decrease in total volatile solids (TVS) indicated effective organic matter conversion, while varying dissolved organic carbon (DOC) levels suggested different degradation rates. Nitrogen analysis (TN) revealed that the differences between variants were due to varying nitrogen processing mechanisms by microorganisms. These results highlight the potential of sizing waste as a substrate for bioH2 production and offer insights for optimizing the process and developing industrial technologies for bioH2 and other valuable products.
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Zhang, Xuechun, Shi Li, Zhibin Zhang, Kin Weng Kong, Zhenxing Wang та Xiahong He. "Chemical Constituents, Antioxidant, and α-Glucosidase Inhibitory Activities of Different Fermented Gynostemma Pentaphyllum Leaves and Untargeted Metabolomic Measurement of the Metabolite Variation". Antioxidants 12, № 8 (2023): 1505. http://dx.doi.org/10.3390/antiox12081505.
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To assess the effects of microbial fermentation on Gynostemma pentaphyllum leaves (GPL), four probiotics were used to ferment GPL (FGPL) for 7 days. At different stages of fermentation, changes in the active components and biological activities of FGPL were determined. The findings suggest that short-term fermentation with probiotics can enhance both the content and bioactivity of active components in GPL. However, prolonged fermentation may lead to a decline in these aspects. Among them, the best effect was observed with SWFU D16 fermentation for 2 days. This significantly improved the total phenolic and total flavonoid content, antioxidant capacity, and inhibitory ability against α-glucosidase activity with an increase of 28%, 114.82%, 7.42%, and 31.8%, respectively. The high-performance liquid chromatography (HPLC) analysis results also supported this trend. Untargeted metabolomics analysis revealed metabolite changes between GPL and FGPL and the key metabolites associated with these functional activities. These key metabolites are mainly organic acids, flavonoids, carbohydrates, terpenoids, and other substances. KEGG analysis demonstrated that microbial metabolism in diverse environments and carbon metabolism were the most significantly enriched pathways. Among them, 3-(3-hydroxyphenyl) propanoic acid, d-glucose, gallic acid, gluconic acid, l-lactic acid, and l-malic acid were mostly involved in the microbial metabolism of diverse environmental pathways. In contrast, D-glucose, gluconic acid, and l-malic acid were mainly related to the carbon metabolism pathway. This study revealed the positive effect of probiotic fermentation on GPL and its potential metabolism mechanism, which could provide supporting data for further research.
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Lin, Long, Ehssan Hosseini Koupaie, Armineh Azizi, et al. "Comparison of Two Process Schemes Combining Hydrothermal Treatment and Acidogenic Fermentation of Source-Separated Organics." Molecules 24, no. 8 (2019): 1466. http://dx.doi.org/10.3390/molecules24081466.
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This study compares the effects of pre- and post-hydrothermal treatment of source- separated organics (SSO) on solubilization of particulate organics and acidogenic fermentation for volatile fatty acids (VFAs) production. The overall COD solubilization and solids removal efficiencies from both schemes were comparable. However, the pre-hydrolysis of SSO followed by acidogenic fermentation resulted in a relatively higher VFA yield of 433 mg/g VSS, which was 18% higher than that of a process scheme with a post-hydrolysis of dewatered solids from the fermentation process. Regarding the composition of VFA, the dominance of acetate and butyrate was comparable in both process schemes, while propionate concentration considerably increased in the process with pre-hydrolysis of SSO. The microbial community results showed that the relative abundance of Firmicutes increased substantially in the fermentation of pretreated SSO, indicating that there might be different metabolic pathways for production of VFAs in fermentation process operated with pre-treated SSO. The possible reason might be that the abundance of soluble organic matters due to pre-hydrolysis might stimulate the growth of more kinetically efficient fermentative bacteria as indicated by the increase in Firmicutes percentage.
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Zhang, Yu-Ting, Yu-Ke Deng, Yong-Fang Zou, et al. "Linking Microbial Functional Gene Abundance and Daqu Extracellular Enzyme Activity: Implications for Carbon Metabolism during Fermentation." Foods 11, no. 22 (2022): 3623. http://dx.doi.org/10.3390/foods11223623.
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Daqu is the starter of Baijiu, it provides the microbes and enzymes necessary for fermentation. Studies have already established carbohydrate metabolism as the primary functional module in Daqu fermentation. The present study investigated the changes in microbial functions and the relationship between carbohydrate metabolism-related functional genes and extracellular enzyme activity during the Daqu fermentation. Amplicon sequencing identified 38 bacterial and 10 fungal phyla in Daqu samples, while shotgun metagenomic sequencing classified and annotated 40.66% of the individual features, of which 40.48% were prokaryotes. KEGG annotation showed that the pathways related to metabolites were less in the early fermentation stage, but higher in the middle and late stages. The functional genes related to pyruvate metabolism, glyoxylate and dicarboxylate metabolism, and propanoate metabolism were relatively high in the early and late stages of fermentation, while that for start and cross metabolism was relatively low. The study also found that amino sugar and nucleoside sugar metabolism were dominant in the middle stage of fermentation. Finally, the correlation network analysis showed that amylase activity positively correlated with many carbon metabolism-related pathways, while liquefaction activity negatively correlated with these pathways. In conclusion, the present study provides a theoretical basis for improving and stabilizing the quality of Daqu.
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Iram, Attia, Ali Özcan, Ercan Yatmaz, İrfan Turhan, and Ali Demirci. "Effect of Microparticles on Fungal Fermentation for Fermentation-Based Product Productions." Processes 10, no. 12 (2022): 2681. http://dx.doi.org/10.3390/pr10122681.
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Ranging from simple food ingredients to complex pharmaceuticals, value-added products via microbial fermentation have many advantages over their chemically synthesized alternatives. Some of such advantages are environment-friendly production pathways, more specificity in the case of enzymes as compared to the chemical catalysts and reduction of harmful chemicals, such as heavy metals or strong acids and bases. Fungal fermentation systems include yeast and filamentous fungal cells based on cell morphology and culture conditions. However, filamentous fungal fermentation has gained attention in the past few decades because of the diversity of microbial products and robust production of some of the most value-added commodities. This type of fungal fermentation is usually carried out by solid-state fermentation. However, solid-state fermentation poses problems during the scale-up for industrial production. Therefore, submerged fermentation for value-added products is usually preferred for scaling-up purposes. The main problem with submerged fungal fermentation is the formation of complex mycelial clumps or pellets. The formation of such pellets increases the viscosity of the media and hinders the efficient transfer of oxygen and nutrient resources in the liquid phase. The cells at the center of the clump or pellet start to die because of a shortage of resources and, thus, productivity decreases substantially. To overcome this problem, various morphological engineering techniques are being researched. One approach is the use of microparticles. Microparticles are inert particles with various size ranges that are used in fermentation. These microparticles are shown to have positive effects, such as high enzyme productivity or smaller pellets with fungal fermentation. Therefore, this review provides a background about the types of microparticles and summarizes some of the recent studies with special emphasis on the fungal morphology changes and microparticle types along with the applications of microparticles in filamentous fungal fermentations.
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Xiang, Yannan, Siyi Tian, Xinyu Luo, et al. "Differential Analysis of Pomelo Peel Fermentation by Cordyceps militaris Based on Untargeted Metabolomics." Processes 12, no. 4 (2024): 687. http://dx.doi.org/10.3390/pr12040687.
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The content of differentially abundant metabolites in the fermentation broth of grapefruit peels fermented by Cordyceps militaris at different fermentation times was analyzed via LC‒MS/MS. Small molecule metabolites and differential metabolic pathways were analyzed via multivariate analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment. A total of 423 metabolites were identified at 0, 2, 6, and 10 days after fermentation. Among them, 169 metabolites showed differential abundance, with significant differences observed between the fermentation liquids of every two experimental groups, and the metabolite composition in the fermentation liquid changed over the fermentation time. In summary, the upregulation and downregulation of metabolites in cancer metabolic pathways collectively promote the remodeling of cancer cell metabolism, facilitating increased glycolysis, alterations in TCA cycle flux, and enhanced biosynthesis of the macromolecules required for rapid proliferation and survival. This study provides new perspectives on the development of high-value-added agricultural and forestry byproducts and the development and research of functional foods.
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Chen, Li, Ke Li, Huitai Chen, and Zongjun Li. "Reviewing the Source, Physiological Characteristics, and Aroma Production Mechanisms of Aroma-Producing Yeasts." Foods 12, no. 18 (2023): 3501. http://dx.doi.org/10.3390/foods12183501.
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Flavor is an essential element of food quality. Flavor can be improved by adding flavoring substances or via microbial fermentation to impart aroma. Aroma-producing yeasts are a group of microorganisms that can produce aroma compounds, providing a strong aroma to foods and thus playing a great role in the modern fermentation industry. The physiological characteristics of aroma-producing yeast, including alcohol tolerance, acid tolerance, and salt tolerance, are introduced in this article, beginning with their origins and biological properties. The main mechanism of aroma-producing yeast is then analyzed based on its physiological roles in the fermentation process. Functional enzymes such as proteases, lipases, and glycosidase are released by yeast during the fermentation process. Sugars, fats, and proteins in the environment can be degraded by these enzymes via pathways such as glycolysis, methoxylation, the Ehrlich pathway, and esterification, resulting in the production of various aromatic esters (such as ethyl acetate and ethyl caproate), alcohols (such as phenethyl alcohol), and terpenes (such as monoterpenes, sesquiterpenes, and squalene). Furthermore, yeast cells can serve as cell synthesis factories, wherein specific synthesis pathways can be introduced into cells using synthetic biology techniques to achieve high-throughput production. In addition, the applications of aroma yeast in the food, pharmaceutical, and cosmetic industries are summarized, and the future development trends of aroma yeasts are discussed to provide a theoretical basis for their application in the food fermentation industry.
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Liu, Wuyang, Hao Zhou, Jing Cai, et al. "Microbial Community Succession and Flavor Compound Formation in Sesame-Flavored Baijiu from Zaopei." Fermentation 11, no. 5 (2025): 255. https://doi.org/10.3390/fermentation11050255.
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The succession of microbial communities during the fermentation process in sesame-flavored Baijiu cellars profoundly influences the flavor profile of the liquor. However, the key factors driving microbial succession in these cellars remain unclear. This study focuses on the fermentation process of sesame-flavored Baijiu Zaopei in traditional Tongcheng cellars. Samples were collected from the surface, middle, and bottom of the cellar, categorized by fermentation time. Various techniques were employed to analyze the physicochemical properties (including moisture, ethanol, total acid, starch, and reducing sugars), flavor compounds (volatile substances and amino acids), and microbial communities (bacteria and fungi) of the Zaopei during fermentation. A total of 68 flavor compounds were detected, with 16 key flavor compounds and 16 amino acids identified. Microbiologically, the Lactobacillus genus dominated in the later stages of fermentation, while the Issatchenkia species were the predominant fungi. Correlation analysis indicated that environmental factors play a significant role in driving microbial community succession. Acetobacter, Staphylococcus, Pichia, Bacillus, and Kroppenstedtia species may contribute to the synthesis of key flavor compounds. The relative contents of acetic acid, 2-phenylethyl ester, and Benzenepropanoic acid ethyl ester were influenced by multiple microbial groups, suggesting a synergistic fermentation effect. PICRUSt2 predictions revealed significant differences in 41 KEGG pathways at level 2 and 293 pathways at level 3 across different fermentation intervals. These pathways are primarily associated with amino acid, ester, and nucleotide metabolism, as well as bacterial transcription, translation, and signal transduction. This research provides a theoretical foundation for understanding the fermentation mechanisms of sesame-flavored Baijiu.
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Koendjbiharie, Jeroen Girwar, Kilian Wiersma, and Richard van Kranenburg. "Investigating the Central Metabolism ofClostridium thermosuccinogenes." Applied and Environmental Microbiology 84, no. 13 (2018): e00363-18. http://dx.doi.org/10.1128/aem.00363-18.
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ABSTRACTClostridium thermosuccinogenesis a thermophilic anaerobic bacterium able to convert various carbohydrates to succinate and acetate as main fermentation products. Genomes of the four publicly available strains have been sequenced, and the genome of the type strain has been closed. The annotated genomes were used to reconstruct the central metabolism, and enzyme assays were used to validate annotations and to determine cofactor specificity. The genes were identified for the pathways to all fermentation products, as well as for the Embden-Meyerhof-Parnas pathway and the pentose phosphate pathway. Notably, a candidate transaldolase was lacking, and transcriptomics during growth on glucose versus that on xylose did not provide any leads to potential transaldolase genes or alternative pathways connecting the C5with the C3/C6metabolism. Enzyme assays showed xylulokinase to prefer GTP over ATP, which could be of importance for engineering xylose utilization in related thermophilic species of industrial relevance. Furthermore, the gene responsible for malate dehydrogenase was identified via heterologous expression inEscherichia coliand subsequent assays with the cell extract, which has proven to be a simple and powerful method for the basal characterization of thermophilic enzymes.IMPORTANCERunning industrial fermentation processes at elevated temperatures has several advantages, including reduced cooling requirements, increased reaction rates and solubilities, and a possibility to perform simultaneous saccharification and fermentation of a pretreated biomass. Most studies with thermophiles so far have focused on bioethanol production.Clostridium thermosuccinogenesseems an attractive production organism for organic acids, succinic acid in particular, from lignocellulosic biomass-derived sugars. This study provides valuable insights into its central metabolism and GTP and PPicofactor utilization.
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Pinu, Farhana R., Lily Stuart, Taylan Topal, Abby Albright, Damian Martin, and Claire Grose. "The Effect of Yeast Inoculation Methods on the Metabolite Composition of Sauvignon Blanc Wines." Fermentation 9, no. 8 (2023): 759. http://dx.doi.org/10.3390/fermentation9080759.
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Evidence from the literature suggests that different inoculation strategies using either active dry yeast (ADY) or freshly prepared yeast cultures affect wine yeast performance, thus altering biomass and many primary and secondary metabolites produced during fermentation. Here, we investigated how different inoculation methods changed the fermentation behaviour and metabolism of a commercial wine yeast. Using a commercial Sauvignon blanc (SB) grape juice, fermentation was carried out with two different inoculum preparation protocols using Saccharomyces cerevisiae X5: rehydration of commercial ADY and preparation of pre-inoculum in a rich laboratory medium. We also determined the effect of different numbers of yeast cells inoculation (varying from 1 × 106 to 1 × 1012) and successive inoculation on fermentation and end-product formation. The yeast inoculation method and number of cells significantly affected the fermentation time. Principal component analysis (PCA) using 60 wine metabolites showed a separation pattern between wines produced from the two inoculation methods. Inoculation methods influenced the production of amino acids and different aroma compounds, including ethyl and acetate esters. Varietal thiols, 3-mercaptohexanol (3MH), and 4-methyl-4-mercaptopentan-2-one (4MMP) in the wines were affected by the inoculation methods and numbers of inoculated cells, while little impact was observed on 3-mercaptohexyl acetate (3MHA) production. Pathway analysis using these quantified metabolites allowed us to identify the most significant pathways, most of which were related to central carbon metabolism, particularly metabolic pathways involving nitrogen and sulphur metabolism. Altogether, these results suggest that inoculation method and number of inoculated cells should be considered in the production of different wine styles.
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Phan, A. D. T., B. A. Williams, G. Netzel, D. Mikkelsen, B. R. D'Arcy, and M. J. Gidley. "Independent fermentation and metabolism of dietary polyphenols associated with a plant cell wall model." Food & Function 11, no. 3 (2020): 2218–30. http://dx.doi.org/10.1039/c9fo02987g.
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The metabolic pathways of polyphenol degradation are not influenced by the presence of plant cell walls during in vitro fermentation, but co-fermentation of cell walls may lead to faster microbial metabolism of polyphenols.
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Merriman, Joseph A., Wei Xu, and Michael G. Caparon. "Central carbon flux controls growth/damage balance for Streptococcus pyogenes." PLOS Pathogens 19, no. 6 (2023): e1011481. http://dx.doi.org/10.1371/journal.ppat.1011481.
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Microbial pathogens balance growth against tissue damage to achieve maximum fitness. Central carbon metabolism is connected to growth, but how it influences growth/damage balance is largely unknown. Here we examined how carbon flux through the exclusively fermentative metabolism of the pathogenic lactic acid bacterium Streptococcus pyogenes impacts patterns of growth and tissue damage. Using a murine model of soft tissue infection, we systematically examined single and pair-wise mutants that constrained carbon flux through the three major pathways that S. pyogenes employs for reduction of the glycolytic intermediate pyruvate, revealing distinct disease outcomes. Its canonical lactic acid pathway (via lactate dehydrogenase) made a minimal contribution to virulence. In contrast, its two parallel pathways for mixed-acid fermentation played important, but non-overlapping roles. Anaerobic mixed acid fermentation (via pyruvate formate lyase) was required for growth in tissue, while aerobic mixed-acid pathway (via pyruvate dehydrogenase) was not required for growth, but instead regulated levels of tissue damage. Infection of macrophages in vitro revealed that pyruvate dehydrogenase was required to prevent phagolysosomal acidification, which altered expression of the immunosuppressive cytokine IL-10. Infection of IL-10 deficient mice confirmed that the ability of aerobic metabolism to regulate levels of IL-10 plays a key role in the ability of S. pyogenes to modulate levels of tissue damage. Taken together, these results show critical non-overlapping roles for anaerobic and aerobic metabolism in soft tissue infection and provide a mechanism for how oxygen and carbon flux act coordinately to regulate growth/damage balance. Therapies targeting carbon flux could be developed to mitigate tissue damage during severe S. pyogenes infection.
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Li, Xuan, Yangyi Zheng, Wenming Cui, Xueyuan Bai, Chaozhi Zhu, and Gaiming Zhao. "Comparative Effects of the Single and Binary Fermentations of Latilactobacillus sakei and Staphylococcus carnosus on the Growth and Metabolomic Profiles of Fermented Beef Sausages." Microorganisms 13, no. 7 (2025): 1523. https://doi.org/10.3390/microorganisms13071523.
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Latilactobacillus sakei (L. sakei) and Staphylococcus carnosus (S. carnosus) are common starters for fermented sausages. However, the mechanism underlying the effects of these two microorganisms on co-cultivation in sausages remains unclear. This study compared the changes in metabolomics following fermentation by L. sakei and S. carnosus individually and in combination. After two days of fermentation, the pH values of the LS (Latilactobacillus Single), SC (Staphylococcus Single), and LSSC (Latilactobacillus-Staphylococcus Combined) groups were 4.59, 5.19, and 4.86. By comparing the common differential metabolites among the three groups, it was found that the content of N2-acetyl-L-ornithine decreased after single fermentation with L. sakei, while the content of N2-acetyl-L-ornithine increased after single fermentation with S. carnosus and combined fermentation with L. sakei. Additionally, KEGG pathway analysis identified eight key metabolic pathways, including purine metabolism, starch and sucrose metabolism. In addition, it was found that L. sakei produced D-Galactose during fermentation, which could be utilized by S. carnosus. The co-fermentation of L. sakei and S. carnosus promoted the production of D-sorbitol. Our results suggest that the metabolic interactions between L. sakei and S. carnosus increase the number of functional metabolites in co-fermented sausages. These findings provide valuable insights and new research directions for the study of LAB and CNS interactions, as well as for the development of fermentation agents.
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Bartos, Hunor, Márta Balázs, Ildikó Hajnalka Kuzman, Szabolcs Lányi, and Ildikó Miklóssy. "Production of High Added-Value Chemicals in Basfia succiniciproducens: Role of Medium Composition." Sustainability 13, no. 6 (2021): 3513. http://dx.doi.org/10.3390/su13063513.
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Succinic acid production through biological fermentation led to new pathways in the integration of renewable feedstock from different industries into biosynthesis. In this article, we investigate the population growth dynamics and succinic acid production potential of the recently isolated natural succinic acid producer, Basfia succiniciproducens, using in silico constraint-based metabolic models as well as in vitro experiments. Our work focuses on the influence of different renewable substrates and added yeast extract on fermentation dynamics, and the produced metabolites of the strain cultured in mineral (minimal) medium. According to our experiments, which were carried out as small-scale fermentations and in bioreactor conditions, glucose is the preferred carbon source, while the addition of 1% yeast extract has a significant positive effect on biomass formation. In the case of B. succiniciproducens cultured in minimal salt medium, a production potential as high as 47.09 mM succinic acid was obtained in these conditions. Industrial applications related to this bacterial strain could contribute to new possibilities for the re-use of byproducts by using fermentation processes, leading to high added-value compounds.
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Wagner, Ellen R., and Audrey P. Gasch. "Advances in S. cerevisiae Engineering for Xylose Fermentation and Biofuel Production: Balancing Growth, Metabolism, and Defense." Journal of Fungi 9, no. 8 (2023): 786. http://dx.doi.org/10.3390/jof9080786.
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Genetically engineering microorganisms to produce chemicals has changed the industrialized world. The budding yeast Saccharomyces cerevisiae is frequently used in industry due to its genetic tractability and unique metabolic capabilities. S. cerevisiae has been engineered to produce novel compounds from diverse sugars found in lignocellulosic biomass, including pentose sugars, like xylose, not recognized by the organism. Engineering high flux toward novel compounds has proved to be more challenging than anticipated since simply introducing pathway components is often not enough. Several studies show that the rewiring of upstream signaling is required to direct products toward pathways of interest, but doing so can diminish stress tolerance, which is important in industrial conditions. As an example of these challenges, we reviewed S. cerevisiae engineering efforts, enabling anaerobic xylose fermentation as a model system and showcasing the regulatory interplay’s controlling growth, metabolism, and stress defense. Enabling xylose fermentation in S. cerevisiae requires the introduction of several key metabolic enzymes but also regulatory rewiring of three signaling pathways at the intersection of the growth and stress defense responses: the RAS/PKA, Snf1, and high osmolarity glycerol (HOG) pathways. The current studies reviewed here suggest the modulation of global signaling pathways should be adopted into biorefinery microbial engineering pipelines to increase efficient product yields.
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Wang, Jilong, Suthamat Niyompanich, Yi-Shu Tai, et al. "Engineering of a Highly Efficient Escherichia coli Strain for Mevalonate Fermentation through Chromosomal Integration." Applied and Environmental Microbiology 82, no. 24 (2016): 7176–84. http://dx.doi.org/10.1128/aem.02178-16.
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ABSTRACTChromosomal integration of heterologous metabolic pathways is optimal for industrially relevant fermentation, as plasmid-based fermentation causes extra metabolic burden and genetic instabilities. In this work, chromosomal integration was adapted for the production of mevalonate, which can be readily converted into β-methyl-δ-valerolactone, a monomer for the production of mechanically tunable polyesters. The mevalonate pathway, driven by a constitutive promoter, was integrated into the chromosome ofEscherichia colito replace the native fermentation geneadhEorldhA. The engineered strains (CMEV-1 and CMEV-2) did not require inducer or antibiotic and showed slightly higher maximal productivities (0.38 to ∼0.43 g/liter/h) and yields (67.8 to ∼71.4% of the maximum theoretical yield) than those of the plasmid-based fermentation. Since the glycolysis pathway is the first module for mevalonate synthesis,atpFHdeletion was employed to improve the glycolytic rate and the production rate of mevalonate. Shake flask fermentation results showed that the deletion ofatpFHin CMEV-1 resulted in a 2.1-fold increase in the maximum productivity. Furthermore, enhancement of the downstream pathway by integrating two copies of the mevalonate pathway genes into the chromosome further improved the mevalonate yield. Finally, our fed-batch fermentation showed that, with deletion of theatpFHandsucAgenes and integration of two copies of the mevalonate pathway genes into the chromosome, the engineered strain CMEV-7 exhibited both high maximal productivity (∼1.01 g/liter/h) and high yield (86.1% of the maximum theoretical yield, 30 g/liter mevalonate from 61 g/liter glucose after 48 h in a shake flask).IMPORTANCEMetabolic engineering has succeeded in producing various chemicals. However, few of these chemicals are commercially competitive with the conventional petroleum-derived materials. In this work, chromosomal integration of the heterologous pathway and subsequent optimization strategies ensure stable and efficient (i.e., high-titer, high-yield, and high-productivity) production of mevalonate, which demonstrates the potential for scale-up fermentation. Among the optimization strategies, we demonstrated that enhancement of the glycolytic flux significantly improved the productivity. This result provides an example of how to tune the carbon flux for the optimal production of exogenous chemicals.