Pub Date : 2025-08-11DOI: 10.3390/fermentation11080460
Lirong Yang, Hui Su, Jian Wang, Sijia Sun, Sibo Liu, Baishuang Yin, Wenlong Dong, Guojiang Li
This study aimed to identify a probiotic bacterium with antagonistic activity against the foodborne pathogen Staphylococcus aureus (S. aureus) and investigate the mechanism of its antibacterial components. Growth kinetics were analyzed to assess bacterial proliferation. Acid and bile salt tolerance are vital indicators for evaluating probiotic survival in the gastrointestinal tract. The results indicated that Companilactobacillus farciminis (C. farciminis) YLR-1 not only had high tolerance to salt conditions (0.03%, 0.3%, and 0.5%) but also has a high survival rate at pH 3–4. The bacteriocin-like inhibitory substance (BLIS) isolated from C. farciminis YLR-1 was dialyzed using a membrane with a molecular weight cut-off (MWCO) of 500 Da, followed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis. The results indicate that the BLIS produced by C. farciminis YLR-1 is a small-molecule peptide. BLIS displayed pH tolerance within acidic and neutral environments (4–8) and exhibited thermostability. When treated with proteinase K, the antibacterial action of BLIS was found to be inactivated. Membrane disruption mechanisms were examined using fluorescence imaging and scanning electron microscopy (SEM). SEM and fluorescence imaging revealed that BLIS-induced membrane damage in S. aureus ATCC 25923 causes cytoplasmic leakage and cell death.
{"title":"Isolation and Characterization of Bacteriocin-like-Producing Companilactobacillus farciminis YLR-1 and the Inhibitory Activity of Bacteriocin Against Staphylococcus aureus","authors":"Lirong Yang, Hui Su, Jian Wang, Sijia Sun, Sibo Liu, Baishuang Yin, Wenlong Dong, Guojiang Li","doi":"10.3390/fermentation11080460","DOIUrl":"https://doi.org/10.3390/fermentation11080460","url":null,"abstract":"This study aimed to identify a probiotic bacterium with antagonistic activity against the foodborne pathogen Staphylococcus aureus (S. aureus) and investigate the mechanism of its antibacterial components. Growth kinetics were analyzed to assess bacterial proliferation. Acid and bile salt tolerance are vital indicators for evaluating probiotic survival in the gastrointestinal tract. The results indicated that Companilactobacillus farciminis (C. farciminis) YLR-1 not only had high tolerance to salt conditions (0.03%, 0.3%, and 0.5%) but also has a high survival rate at pH 3–4. The bacteriocin-like inhibitory substance (BLIS) isolated from C. farciminis YLR-1 was dialyzed using a membrane with a molecular weight cut-off (MWCO) of 500 Da, followed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis. The results indicate that the BLIS produced by C. farciminis YLR-1 is a small-molecule peptide. BLIS displayed pH tolerance within acidic and neutral environments (4–8) and exhibited thermostability. When treated with proteinase K, the antibacterial action of BLIS was found to be inactivated. Membrane disruption mechanisms were examined using fluorescence imaging and scanning electron microscopy (SEM). SEM and fluorescence imaging revealed that BLIS-induced membrane damage in S. aureus ATCC 25923 causes cytoplasmic leakage and cell death.","PeriodicalId":507249,"journal":{"name":"Fermentation","volume":"11 8","pages":"460-460"},"PeriodicalIF":0.0,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.mdpi.com/2311-5637/11/8/460/pdf?version=1754904952","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147333441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-31DOI: 10.3390/fermentation11080439
Lu Wang, Junping Fan, Xiao He, Jian Cheng, Xinyan Zhang, Tian Tian, Yonghao Li
The β-glucosidase CEL1B has been linked to regulating cellulase expression in Trichoderma reesei, yet its inducer-specific functions and broader regulatory roles remain poorly characterized. In this study, CRISPR-Cas9-mediated gene knockout was applied in the industrial high-producing T. reesei Rut C30 to investigate CEL1B function without the confounding effects of KU70 deletion. Unlike previous studies focused solely on cellulose or lactose induction, transcriptomic analysis of the CEL1B knockout strain revealed its regulatory roles under both lactose- and sophorose-rich conditions, with sophorose representing the most potent natural inducer of cellulase expression. Under lactose induction, CEL1B deletion resulted in a 52.4% increase in cellulase activity (p < 0.05), accompanied by transcriptome-wide upregulation of β-glucosidase genes (CEL3A: 729%, CEL3D: 666.8%, CEL3C: 110.9%), cellulose-sensing receptors (CRT1: 203.0%, CRT2: 105.8%), and key transcription factors (XYR1: 2.7-fold, ACE3: 2.8-fold, VIB1: 2.1-fold). Expression of ER proteostasis genes was significantly upregulated (BIP1: 3.3-fold, HSP70: 6.2-fold), contributing to enhanced enzyme secretion. Conversely, under sophorose induction, CEL1B deletion reduced cellulase activity by 25.7% (p < 0.05), which was associated with transcriptome profiling showing significant downregulation of β-glucosidase CEL3H (66.6%) and cellodextrin transporters (TrireC30_91594: 79.3%, TrireC30_127980: 76.3%), leading to reduced cellobiohydrolase expression (CEL7A: 57.8%, CEL6A: 67.8%). This first transcriptomic characterization of the CEL1B knockout strain reveals its dual opposing roles in modulating cellulase expression in response to lactose versus sophorose, providing new strategies for optimizing inducer-specific enzyme production in T. reesei.
{"title":"Transcriptomic Analysis Reveals Opposing Roles of CEL1B in Sophorose- and Lactose-Induced Cellulase Expression in Trichoderma reesei Rut C30","authors":"Lu Wang, Junping Fan, Xiao He, Jian Cheng, Xinyan Zhang, Tian Tian, Yonghao Li","doi":"10.3390/fermentation11080439","DOIUrl":"https://doi.org/10.3390/fermentation11080439","url":null,"abstract":"The β-glucosidase CEL1B has been linked to regulating cellulase expression in Trichoderma reesei, yet its inducer-specific functions and broader regulatory roles remain poorly characterized. In this study, CRISPR-Cas9-mediated gene knockout was applied in the industrial high-producing T. reesei Rut C30 to investigate CEL1B function without the confounding effects of KU70 deletion. Unlike previous studies focused solely on cellulose or lactose induction, transcriptomic analysis of the CEL1B knockout strain revealed its regulatory roles under both lactose- and sophorose-rich conditions, with sophorose representing the most potent natural inducer of cellulase expression. Under lactose induction, CEL1B deletion resulted in a 52.4% increase in cellulase activity (p < 0.05), accompanied by transcriptome-wide upregulation of β-glucosidase genes (CEL3A: 729%, CEL3D: 666.8%, CEL3C: 110.9%), cellulose-sensing receptors (CRT1: 203.0%, CRT2: 105.8%), and key transcription factors (XYR1: 2.7-fold, ACE3: 2.8-fold, VIB1: 2.1-fold). Expression of ER proteostasis genes was significantly upregulated (BIP1: 3.3-fold, HSP70: 6.2-fold), contributing to enhanced enzyme secretion. Conversely, under sophorose induction, CEL1B deletion reduced cellulase activity by 25.7% (p < 0.05), which was associated with transcriptome profiling showing significant downregulation of β-glucosidase CEL3H (66.6%) and cellodextrin transporters (TrireC30_91594: 79.3%, TrireC30_127980: 76.3%), leading to reduced cellobiohydrolase expression (CEL7A: 57.8%, CEL6A: 67.8%). This first transcriptomic characterization of the CEL1B knockout strain reveals its dual opposing roles in modulating cellulase expression in response to lactose versus sophorose, providing new strategies for optimizing inducer-specific enzyme production in T. reesei.","PeriodicalId":507249,"journal":{"name":"Fermentation","volume":"11 8","pages":"439-439"},"PeriodicalIF":0.0,"publicationDate":"2025-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.mdpi.com/2311-5637/11/8/439/pdf?version=1753951373","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147332478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-09DOI: 10.3390/fermentation11060331
Chang Yu Liu, Xuefeng Xiao, Wenzhong Xing, Renuka Na, Y. J. Song, Guoqiang Cao, Pengchao Wang
Mandelic acid (MA) is a valuable α-hydroxy acid with applications in pharmaceuticals, cosmetics, and fine chemicals. While chemical synthesis is well established, concerns over toxicity and sustainability have driven interest in microbial production. Here, we engineered Escherichia coli for de novo MA biosynthesis by integrating enzyme screening, metabolic flux optimization, and pathway regulation. We first screened and identified an efficient hydroxymandelate synthase (HMAS) homolog from Actinosynnema mirum for MA synthesis, and subsequently enhanced the shikimate pathway along with the supply of the precursors erythrose-4-phosphate (E4P) and phosphoenolpyruvate (PEP). Additionally, CRISPR interference (CRISPRi) was employed to repress competing pathways and redirect flux toward MA production. High-cell-density cultivation (HCDC) in a 5 L bioreactor demonstrated the strain’s industrial potential, achieving an MA titer of 9.58 g/L, the highest reported for microbial production. This study provides a systematic metabolic engineering approach for efficient MA biosynthesis from glucose, offering a foundation for sustainable large-scale production, demonstrating not only genetic-level optimizations, but also effective process scaling through high-cell-density cultivation, highlighting the power of pathway engineering in microbial cell factories.
{"title":"Metabolic Engineering of Escherichia coli for De Novo Biosynthesis of Mandelic Acid","authors":"Chang Yu Liu, Xuefeng Xiao, Wenzhong Xing, Renuka Na, Y. J. Song, Guoqiang Cao, Pengchao Wang","doi":"10.3390/fermentation11060331","DOIUrl":"https://doi.org/10.3390/fermentation11060331","url":null,"abstract":"Mandelic acid (MA) is a valuable α-hydroxy acid with applications in pharmaceuticals, cosmetics, and fine chemicals. While chemical synthesis is well established, concerns over toxicity and sustainability have driven interest in microbial production. Here, we engineered Escherichia coli for de novo MA biosynthesis by integrating enzyme screening, metabolic flux optimization, and pathway regulation. We first screened and identified an efficient hydroxymandelate synthase (HMAS) homolog from Actinosynnema mirum for MA synthesis, and subsequently enhanced the shikimate pathway along with the supply of the precursors erythrose-4-phosphate (E4P) and phosphoenolpyruvate (PEP). Additionally, CRISPR interference (CRISPRi) was employed to repress competing pathways and redirect flux toward MA production. High-cell-density cultivation (HCDC) in a 5 L bioreactor demonstrated the strain’s industrial potential, achieving an MA titer of 9.58 g/L, the highest reported for microbial production. This study provides a systematic metabolic engineering approach for efficient MA biosynthesis from glucose, offering a foundation for sustainable large-scale production, demonstrating not only genetic-level optimizations, but also effective process scaling through high-cell-density cultivation, highlighting the power of pathway engineering in microbial cell factories.","PeriodicalId":507249,"journal":{"name":"Fermentation","volume":"11 6","pages":"331-331"},"PeriodicalIF":0.0,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147333285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-06DOI: 10.3390/fermentation11060325
Yifan Li, Zhen Chen, Wei Hong, Tao Feng, Xiwei Tian, Ju Chu
To better analyze the biosynthesis mechanism of cephalosporin C (CPC) in Acremonium chrysogenum, single-factor omission experiments and Plackett–Burman (PB) experimental design were employed to identify key components in the chemically defined medium. Response surface methodology (RSM) was then applied to optimize the concentrations of critical factors, achieving a final CPC titer of 4.70 g/L, which reached 59.54% of the titer obtained with complex medium. Methionine was identified as the most significant amino acid influencing CPC production during medium optimization. On the basis of these findings, transcriptomic analysis was conducted to elucidate the regulatory role of methionine. The results revealed that methionine enhances CPC biosynthesis by upregulating cysteine metabolism-related genes and activating primary metabolic pathways to supply precursors and energy for secondary metabolism. Additionally, methionine promoted hyphal swelling and arthrospore formation, leading to the upregulated expression of genes in CPC biosynthetic gene clusters. By integrating medium optimization with transcriptomic analysis, we provided more reliable insights into the regulatory role of methionine in A. chrysogenum growth and CPC biosynthesis using a chemically defined medium, offering valuable guidance for fermentation process optimization and subsequent metabolic engineering strategies.
{"title":"Application of Transcriptome Analysis for the Exploration of the Mechanism of Methionine Promoting the Synthesis of Cephalosporin C in Acremonium chrysogenum by Employing a Chemically Defined Medium","authors":"Yifan Li, Zhen Chen, Wei Hong, Tao Feng, Xiwei Tian, Ju Chu","doi":"10.3390/fermentation11060325","DOIUrl":"https://doi.org/10.3390/fermentation11060325","url":null,"abstract":"To better analyze the biosynthesis mechanism of cephalosporin C (CPC) in Acremonium chrysogenum, single-factor omission experiments and Plackett–Burman (PB) experimental design were employed to identify key components in the chemically defined medium. Response surface methodology (RSM) was then applied to optimize the concentrations of critical factors, achieving a final CPC titer of 4.70 g/L, which reached 59.54% of the titer obtained with complex medium. Methionine was identified as the most significant amino acid influencing CPC production during medium optimization. On the basis of these findings, transcriptomic analysis was conducted to elucidate the regulatory role of methionine. The results revealed that methionine enhances CPC biosynthesis by upregulating cysteine metabolism-related genes and activating primary metabolic pathways to supply precursors and energy for secondary metabolism. Additionally, methionine promoted hyphal swelling and arthrospore formation, leading to the upregulated expression of genes in CPC biosynthetic gene clusters. By integrating medium optimization with transcriptomic analysis, we provided more reliable insights into the regulatory role of methionine in A. chrysogenum growth and CPC biosynthesis using a chemically defined medium, offering valuable guidance for fermentation process optimization and subsequent metabolic engineering strategies.","PeriodicalId":507249,"journal":{"name":"Fermentation","volume":"11 6","pages":"325-325"},"PeriodicalIF":0.0,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.mdpi.com/2311-5637/11/6/325/pdf?version=1749203320","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147333752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-05-13DOI: 10.3390/fermentation11050280
Yini Shi, Huan Wang, Zhongke Sun, Zifu Ni, Chengwei Li
Prebiotics are food ingredients that result in specific changes in the composition and/or activity of the gastrointestinal microbiota, thus conferring benefits upon host health. Xylooligosaccharides (XOS) are prebiotic fibers made from xylan. Commercial XOS are mixtures of oligosaccharides containing β-1,4–linked xylose residues. Though they are widely added to foods at different doses, the molecular mechanisms of the catabolism and growth promotion of XOS in the innate gut microbes Lactobacillus spp. remain unknown. In this study, we evaluated the growth-promoting effect using a human fecal isolate, Lactiplantibacillus plantarum strain B20 (Lb. plantarum B20). Assays of bacterial growth and lactic acid production showed stronger growth promotion of XOS than other oligosaccharides did, in a dose- and fraction-dependent pattern. Using the Lb. plantarum strain SK151 genome as a reference, bioinformatic analysis failed to identify any previously characterized genes responsible for the uptake and catabolism of XOS. However, transcriptomic analysis of Lb. plantarum B20 yielded numerous differentially expressed genes (DEGs) during fermentation of XOS. Among these, an oligopeptide ABC transporter (RS03575-03595, composed of five proteins) and a hydrolase (RS06170) were significantly upregulated. Molecular docking analysis indicated that the substrate-binding protein RS03575 may mediate the import of XOS into the cell. Enzymatic assays further demonstrated that RS06170 possesses β-xylosidase activity and can effectively degrade XOS. In addition, functional enrichment analysis suggested that the growth-promoting effect of XOS may be attributed to the upregulation of genes involved in cellular component biogenesis and cell division, potentially through modulation of ribosome function and carbohydrate metabolism in Lb. plantarum B20. These results provide valuable insights into the mechanisms by which XOS promote growth and highlight potential targets for enhancing prebiotic–probiotic interactions.
益生元是导致胃肠道微生物群组成和/或活性发生特定变化的食品成分，从而对宿主健康有益。低聚木糖（XOS）是由木聚糖制成的益生元纤维。商用XOS是含有β-1,4连接木糖残基的低聚糖混合物。虽然它们以不同的剂量被广泛添加到食物中，但XOS在先天肠道微生物乳酸菌中的分解代谢和促进生长的分子机制尚不清楚。在这项研究中，我们利用人类粪便分离物植物乳杆菌B20菌株（Lb. plantarum B20）来评估其促生长作用。细菌生长和乳酸生成的实验表明，XOS比其他低聚糖具有更强的生长促进作用，并呈剂量和部分依赖模式。以植物Lb. plantarum菌株SK151基因组为参照，生物信息学分析未能发现任何先前表征的与XOS摄取和分解代谢有关的基因。然而，植物Lb. plantarum B20的转录组学分析发现，在XOS发酵过程中存在大量差异表达基因（DEGs）。其中，寡肽ABC转运蛋白（RS03575-03595，由5个蛋白组成）和水解酶（RS06170）显著上调。分子对接分析表明底物结合蛋白RS03575可能介导XOS进入细胞。酶促实验进一步证实，RS06170具有β-木糖苷酶活性，能有效降解XOS。此外，功能富集分析表明，XOS的促生长作用可能与上调参与细胞组分生物发生和细胞分裂的基因有关，可能通过调节植物Lb. plantarum B20的核糖体功能和碳水化合物代谢。这些结果为XOS促进生长的机制提供了有价值的见解，并突出了增强益生元-益生菌相互作用的潜在靶点。
{"title":"Catabolism Mechanism and Growth-Promoting Effect of Xylooligosaccharides in Lactiplantibacillus plantarum Strain B20","authors":"Yini Shi, Huan Wang, Zhongke Sun, Zifu Ni, Chengwei Li","doi":"10.3390/fermentation11050280","DOIUrl":"https://doi.org/10.3390/fermentation11050280","url":null,"abstract":"Prebiotics are food ingredients that result in specific changes in the composition and/or activity of the gastrointestinal microbiota, thus conferring benefits upon host health. Xylooligosaccharides (XOS) are prebiotic fibers made from xylan. Commercial XOS are mixtures of oligosaccharides containing β-1,4–linked xylose residues. Though they are widely added to foods at different doses, the molecular mechanisms of the catabolism and growth promotion of XOS in the innate gut microbes Lactobacillus spp. remain unknown. In this study, we evaluated the growth-promoting effect using a human fecal isolate, Lactiplantibacillus plantarum strain B20 (Lb. plantarum B20). Assays of bacterial growth and lactic acid production showed stronger growth promotion of XOS than other oligosaccharides did, in a dose- and fraction-dependent pattern. Using the Lb. plantarum strain SK151 genome as a reference, bioinformatic analysis failed to identify any previously characterized genes responsible for the uptake and catabolism of XOS. However, transcriptomic analysis of Lb. plantarum B20 yielded numerous differentially expressed genes (DEGs) during fermentation of XOS. Among these, an oligopeptide ABC transporter (RS03575-03595, composed of five proteins) and a hydrolase (RS06170) were significantly upregulated. Molecular docking analysis indicated that the substrate-binding protein RS03575 may mediate the import of XOS into the cell. Enzymatic assays further demonstrated that RS06170 possesses β-xylosidase activity and can effectively degrade XOS. In addition, functional enrichment analysis suggested that the growth-promoting effect of XOS may be attributed to the upregulation of genes involved in cellular component biogenesis and cell division, potentially through modulation of ribosome function and carbohydrate metabolism in Lb. plantarum B20. These results provide valuable insights into the mechanisms by which XOS promote growth and highlight potential targets for enhancing prebiotic–probiotic interactions.","PeriodicalId":507249,"journal":{"name":"Fermentation","volume":"11 5","pages":"280-280"},"PeriodicalIF":0.0,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147333943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-15DOI: 10.3390/fermentation11040215
Jing Huang, Jiao Chen, Xiaohui Li
Starter culture significantly influences the texture and flavor of yogurt, making the selection of appropriate fermentation strains a key focus in yogurt starter research. In this study, protease-producing Lactiplantibacillus plantarum NH-24, identified in prior experiments, was combined with Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophiles for yogurt fermentation. Indicators such as coagulation state, acidity, and water-holding capacity were measured to determine the optimal fermentation temperature and starter ratio. Additionally, the effects of this strain on the yogurt’s texture, sensory properties, and volatile flavor compounds were evaluated. The results indicate that a fermentation temperature of 37 °C and a starter ratio of 4:4:3 were most suitable for yogurt production. Further analysis demonstrated that incorporating Lp. plantarum NH-24 improved the yogurt’s texture and flavor while reducing post-acidification during storage. Thus, protease-producing Lp. plantarum NH-24 holds significant promise as a yogurt starter culture.
{"title":"Preliminary Study on the Application of Protease-Producing Lactiplantibacillus plantarum in Yogurt Fermentation","authors":"Jing Huang, Jiao Chen, Xiaohui Li","doi":"10.3390/fermentation11040215","DOIUrl":"https://doi.org/10.3390/fermentation11040215","url":null,"abstract":"Starter culture significantly influences the texture and flavor of yogurt, making the selection of appropriate fermentation strains a key focus in yogurt starter research. In this study, protease-producing Lactiplantibacillus plantarum NH-24, identified in prior experiments, was combined with Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophiles for yogurt fermentation. Indicators such as coagulation state, acidity, and water-holding capacity were measured to determine the optimal fermentation temperature and starter ratio. Additionally, the effects of this strain on the yogurt’s texture, sensory properties, and volatile flavor compounds were evaluated. The results indicate that a fermentation temperature of 37 °C and a starter ratio of 4:4:3 were most suitable for yogurt production. Further analysis demonstrated that incorporating Lp. plantarum NH-24 improved the yogurt’s texture and flavor while reducing post-acidification during storage. Thus, protease-producing Lp. plantarum NH-24 holds significant promise as a yogurt starter culture.","PeriodicalId":507249,"journal":{"name":"Fermentation","volume":"11 4","pages":"215-215"},"PeriodicalIF":0.0,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.mdpi.com/2311-5637/11/4/215/pdf?version=1744711006","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147331947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Termitomyces, a rare edible fungus with both nutritional and medicinal value, has garnered significant attention for its antioxidant properties. This study aims to elucidate the effects of various nutritional components on the antioxidant activity of Termitomyces. Through assays including FRAP, DPPH, ABTS, and •OH scavenging activity, strain XNQL025, which exhibits high antioxidant activity, was identified. Subsequent optimization of culture medium components using single-factor experiments and response surface methodology revealed that aspartic acid (Asp) significantly enhances the antioxidant capacity of this strain. Transcriptomic analysis showed that Asp activates key pathways, including glycolysis/gluconeogenesis, propanoate metabolism, amino sugar and nucleotide sugar metabolism, valine–leucine–isoleucine biosynthesis, and tryptophan metabolism, along with modulating the peroxisome and mitogen-activated protein kinase (MAPK) signaling pathways. These regulatory actions promote the synthesis of antioxidant compounds and establish a multi-layered antioxidant defense system comprising enzymatic (catalase) and non-enzymatic (leucine/chitooligosaccharides) components. The synergistic interaction between these systems significantly strengthens the antioxidant defense capacity of Termitomyces. This study is the first to elucidate the molecular network by which Asp enhances the antioxidant activity of Termitomyces, thereby providing a foundation for its development as a natural antioxidant.
{"title":"Optimization of Fermentation and Transcriptomic Analysis: The Impact of Aspartic Acid on the Antioxidant Activity of Termitomyces","authors":"Jin Zhou, Wenhui Yi, Yunfan Yang, Jiahui Peng, Wujie Zhong, Xuefeng Xu","doi":"10.3390/fermentation11040202","DOIUrl":"https://doi.org/10.3390/fermentation11040202","url":null,"abstract":"Termitomyces, a rare edible fungus with both nutritional and medicinal value, has garnered significant attention for its antioxidant properties. This study aims to elucidate the effects of various nutritional components on the antioxidant activity of Termitomyces. Through assays including FRAP, DPPH, ABTS, and •OH scavenging activity, strain XNQL025, which exhibits high antioxidant activity, was identified. Subsequent optimization of culture medium components using single-factor experiments and response surface methodology revealed that aspartic acid (Asp) significantly enhances the antioxidant capacity of this strain. Transcriptomic analysis showed that Asp activates key pathways, including glycolysis/gluconeogenesis, propanoate metabolism, amino sugar and nucleotide sugar metabolism, valine–leucine–isoleucine biosynthesis, and tryptophan metabolism, along with modulating the peroxisome and mitogen-activated protein kinase (MAPK) signaling pathways. These regulatory actions promote the synthesis of antioxidant compounds and establish a multi-layered antioxidant defense system comprising enzymatic (catalase) and non-enzymatic (leucine/chitooligosaccharides) components. The synergistic interaction between these systems significantly strengthens the antioxidant defense capacity of Termitomyces. This study is the first to elucidate the molecular network by which Asp enhances the antioxidant activity of Termitomyces, thereby providing a foundation for its development as a natural antioxidant.","PeriodicalId":507249,"journal":{"name":"Fermentation","volume":"11 4","pages":"202-202"},"PeriodicalIF":0.0,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147332849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-07DOI: 10.3390/fermentation11040195
Bo Peng, Liyue Fei, Ziyi Lu, Yuejian Mao, Qin Zhang, Xinxin Zhao, Fengxian Tang, Chunhui Shan, Dongsheng Zhang, Wenchao Cai
Sea buckthorn juice (SBJ) has a sour taste and can lead to the demineralization of tooth enamel when consumed over a long period of time, whereas fermentation reduces the acidity of sea buckthorn juice, improves its taste, and enhances its antioxidant activity. Flavor components are important factors that affect the quality of fermented beverages. Yeast is one of the most important factors affecting the flavor of beverages during the fermentation process, where yeast converts sugars into alcohol and produces flavor substances. Therefore, two commercial yeast strains, Angel RW and Angel RV171, were selected in this study for the single and mixed bacterial fermentation of sea buckthorn juice (FSBJ). Physicochemical analyses showed that RV171-FSBJ had the highest total reducing sugar (0.069 ± 0.02 g/L) and total acid content (1.86 ± 0.03 g/L), as well as the highest fermentation efficiency and free radical scavenging capacity (1,1-diphenyl-2-picrylhydrazyl (DPPH) 98.54 ± 0.03%, 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) 88.35 ± 0.14%, ·OH 48.61 ± 0.4%). RWRV-FSBJ had the highest content of functional compounds (total flavonoid content (TFC): 176.09 ± 0.44 μg/mL; total phenolic content (TPC): 157.9 ± 1.35 μg/mL; total anthocyanin concentration (TAC): 0.04 ± 0.004 μg/mL) and good color (L* 50.53 ± 0.04, a* 27.98 ± 0.04, b* 173.64 ± 0.34). Among the three FSBJs, a total of 54 volatile compounds were identified, with RV171-FSBJ having the highest content of volatile compounds. OAV analysis showed that 15, 14, and 11 volatile compounds of RW, RV, and RWRV, respectively, were greater than 1. Among them, ethyl hexanoate had the highest OAV, followed by ethyl isovalerate, phenylethyl alcohol, and 3-methylbutyl 3-methylbutanoate, which are characteristic flavor substances common to FSBJ.
{"title":"Effects of Different Yeasts on the Physicochemical Properties and Aroma Compounds of Fermented Sea Buckthorn Juice","authors":"Bo Peng, Liyue Fei, Ziyi Lu, Yuejian Mao, Qin Zhang, Xinxin Zhao, Fengxian Tang, Chunhui Shan, Dongsheng Zhang, Wenchao Cai","doi":"10.3390/fermentation11040195","DOIUrl":"https://doi.org/10.3390/fermentation11040195","url":null,"abstract":"Sea buckthorn juice (SBJ) has a sour taste and can lead to the demineralization of tooth enamel when consumed over a long period of time, whereas fermentation reduces the acidity of sea buckthorn juice, improves its taste, and enhances its antioxidant activity. Flavor components are important factors that affect the quality of fermented beverages. Yeast is one of the most important factors affecting the flavor of beverages during the fermentation process, where yeast converts sugars into alcohol and produces flavor substances. Therefore, two commercial yeast strains, Angel RW and Angel RV171, were selected in this study for the single and mixed bacterial fermentation of sea buckthorn juice (FSBJ). Physicochemical analyses showed that RV171-FSBJ had the highest total reducing sugar (0.069 ± 0.02 g/L) and total acid content (1.86 ± 0.03 g/L), as well as the highest fermentation efficiency and free radical scavenging capacity (1,1-diphenyl-2-picrylhydrazyl (DPPH) 98.54 ± 0.03%, 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) 88.35 ± 0.14%, ·OH 48.61 ± 0.4%). RWRV-FSBJ had the highest content of functional compounds (total flavonoid content (TFC): 176.09 ± 0.44 μg/mL; total phenolic content (TPC): 157.9 ± 1.35 μg/mL; total anthocyanin concentration (TAC): 0.04 ± 0.004 μg/mL) and good color (L* 50.53 ± 0.04, a* 27.98 ± 0.04, b* 173.64 ± 0.34). Among the three FSBJs, a total of 54 volatile compounds were identified, with RV171-FSBJ having the highest content of volatile compounds. OAV analysis showed that 15, 14, and 11 volatile compounds of RW, RV, and RWRV, respectively, were greater than 1. Among them, ethyl hexanoate had the highest OAV, followed by ethyl isovalerate, phenylethyl alcohol, and 3-methylbutyl 3-methylbutanoate, which are characteristic flavor substances common to FSBJ.","PeriodicalId":507249,"journal":{"name":"Fermentation","volume":"11 4","pages":"195-195"},"PeriodicalIF":0.0,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.mdpi.com/2311-5637/11/4/195/pdf?version=1744012693","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147331471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Neo-allo-ocimene is a monoterpene which could be applied in pesticides, fragrances, and sustainable polymers. In this study, we mined a terpene synthase, AgTPS40, from the transcriptome of celery leaf tissues. Through sequence and phylogenetic analysis, AgTPS40 was characterized as a monoterpene synthase. The AgTPS40 gene was introduced into a heterologous mevalonate pathway hosted in Escherichia coli to enable terpene production. Gas chromatography–mass spectrometry analysis confirmed that AgTPS40 catalyzes the formation of neo-allo-ocimene, marking the first reported identification of a neo-allo-ocimene synthase. Subsequently, we optimized the fermentation conditions and achieved a yield of 933.35 mg/L in a 1 L shake flask, which represents the highest reported titer of neo-allo-ocimene to date. These results reveal the molecular basis of neo-allo-ocimene synthesis in celery and provide a sustainable way to obtain this compound.
{"title":"Microbial Synthesis of Neo-Allo-Ocimene by Celery-Derived Neo-Allo-Ocimene Synthase","authors":"Zheng Liu, Ting Gao, Shaoheng Bao, Penggang Han, Ge Yao, Tianyu Song, Longbao Zhu, Chang Chen, Hui Jiang","doi":"10.3390/fermentation11030153","DOIUrl":"https://doi.org/10.3390/fermentation11030153","url":null,"abstract":"Neo-allo-ocimene is a monoterpene which could be applied in pesticides, fragrances, and sustainable polymers. In this study, we mined a terpene synthase, AgTPS40, from the transcriptome of celery leaf tissues. Through sequence and phylogenetic analysis, AgTPS40 was characterized as a monoterpene synthase. The AgTPS40 gene was introduced into a heterologous mevalonate pathway hosted in Escherichia coli to enable terpene production. Gas chromatography–mass spectrometry analysis confirmed that AgTPS40 catalyzes the formation of neo-allo-ocimene, marking the first reported identification of a neo-allo-ocimene synthase. Subsequently, we optimized the fermentation conditions and achieved a yield of 933.35 mg/L in a 1 L shake flask, which represents the highest reported titer of neo-allo-ocimene to date. These results reveal the molecular basis of neo-allo-ocimene synthesis in celery and provide a sustainable way to obtain this compound.","PeriodicalId":507249,"journal":{"name":"Fermentation","volume":"11 3","pages":"153-153"},"PeriodicalIF":0.0,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.mdpi.com/2311-5637/11/3/153/pdf?version=1742294362","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147332846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D-tagatose is an ideal sucrose substitute with potential applications in food and healthcare. The combined catalysis of polyphosphate kinase (PPK), fructose kinase (FRK), D-tagatose-6-phosphate 3-differential anisomerase (FbaA) and phytase provides a low-cost and convenient pathway for the biosynthesis of D-tagatose from D-fructose; however, there is still a problem of low catalytic efficiency that needs to be solved urgently. Therefore, this study enhanced the biosynthesis of D-tagatose by optimizing the expression levels of PPK, FRK and FbaA in a polycistronic system and knocking out the gene pfka of Escherichia coli. With 30 g/L D-fructose as a substrate, the conversion rate increased to 52%, which was the highest after 24 h. In addition, by constructing a multienzyme self-assembly system with SpyTag and SpyCatcher to improve the whole-cell catalytic ability, the conversion rate was further increased to 75%. Finally, through the fed-batch strategy, the optimal strain Ec-7 produced 68.1 g/L D-tagatose from 100 g/L D-fructose. The multienzyme cascade route reported herein provides an efficient and elegant innovative solution for the generation of D-tagatose.
{"title":"Construction of Efficient Multienzyme Cascade Reactions for D-Tagatose Biosynthesis from D-Fructose","authors":"Peiyu Miao, Qiang Wang, Kexin Ren, Tongtong Xu, Zigang Zhang, Ruying Hu, Meijuan Xu, Zhiming Rao, Xian Zhang","doi":"10.3390/fermentation11030139","DOIUrl":"https://doi.org/10.3390/fermentation11030139","url":null,"abstract":"D-tagatose is an ideal sucrose substitute with potential applications in food and healthcare. The combined catalysis of polyphosphate kinase (PPK), fructose kinase (FRK), D-tagatose-6-phosphate 3-differential anisomerase (FbaA) and phytase provides a low-cost and convenient pathway for the biosynthesis of D-tagatose from D-fructose; however, there is still a problem of low catalytic efficiency that needs to be solved urgently. Therefore, this study enhanced the biosynthesis of D-tagatose by optimizing the expression levels of PPK, FRK and FbaA in a polycistronic system and knocking out the gene pfka of Escherichia coli. With 30 g/L D-fructose as a substrate, the conversion rate increased to 52%, which was the highest after 24 h. In addition, by constructing a multienzyme self-assembly system with SpyTag and SpyCatcher to improve the whole-cell catalytic ability, the conversion rate was further increased to 75%. Finally, through the fed-batch strategy, the optimal strain Ec-7 produced 68.1 g/L D-tagatose from 100 g/L D-fructose. The multienzyme cascade route reported herein provides an efficient and elegant innovative solution for the generation of D-tagatose.","PeriodicalId":507249,"journal":{"name":"Fermentation","volume":"11 3","pages":"139-139"},"PeriodicalIF":0.0,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.mdpi.com/2311-5637/11/3/139/pdf?version=1741792676","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147332204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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