Microbial Cell Factories最新文献

{"title":"Advances in the heterologous biosynthesis of QS saponins: a review.","authors":"Yanjie Tian, Wanze Zhang, Min Tang, Mingzhang Wen, Jianjun Qiao, Hongji Zhu, Weiguo Li, Qinggele Caiyin","doi":"10.1186/s12934-026-03034-6","DOIUrl":"10.1186/s12934-026-03034-6","url":null,"abstract":"<p><p>QS saponins are a type of triterpenoid glycosides derived from the bark of Quillaja saponaria (Chilean soapbark tree). They are widely used in detergents, food and cosmetics, especially as vaccine adjuvants, due to their cleansing function and immunostimulatory activities. Among these compounds, QS-21 stands out as one of the most potent adjuvants in modern vaccinology due to its remarkable capacity to enhance antigen-specific immunogenicity and elicit robust immune responses. It shows potential for development in both human and veterinary vaccine research. With the rise of synthetic biology technology, the production of QS saponins using microbial cell factories has become a research hotspot. The review systematically summarizes the mechanism of action and practical applications of the most promising QS saponin QS-21, and outlines the biosynthesis pathways of QS saponins, with a focus on exploring the synthetic biology strategies employed for the microbial synthesis of QS saponins. In addition, targeted response strategies have been proposed for the current research challenges. This review aims to lay a theoretical foundation for promoting the medical utilization and sustainable production of QS saponins.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13393811/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148032618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fungal exopolysaccharides as next-generation microbial biomaterials: molecular biosynthesis, structural architecture, and translational biomanufacturing strategies.","authors":"Hassan A H Ibrahim, Yasser H El-Halmouch, Dalia El Badan, Rana Diab, Sameh S Ali","doi":"10.1186/s12934-026-03002-0","DOIUrl":"10.1186/s12934-026-03002-0","url":null,"abstract":"<p><p>Fungal exopolysaccharides (EPSs) are increasingly recognized as structurally programmable microbial polymers with applications spanning biomedicine, materials engineering, food systems, and environmental technologies. While previous reviews have often addressed fungal EPS diversity, production variables, or application domains separately, an integrated framework linking biosynthesis, molecular architecture, process control, and translational manufacturing remains underdeveloped. This review positions fungal EPSs as next-generation biomaterials by integrating (i) biochemical and genetic regulation of EPS biosynthesis, (ii) structure-function mapping across major polymer classes, (iii) cultivation and downstream processing workflows that enable reproducible product specifications, and (iv) industrial translation pathways within scalable and sustainability-aligned biomanufacturing systems. Gene-cluster-resolved case studies and process-to-product design principles illustrate how metabolic flux, fermentation parameters, and polymer modification shape functional performance. Current bottlenecks-including strain-dependent variability, purification complexity, quality harmonization, and techno-economic constraints-are critically evaluated to distinguish laboratory potential from scalable feasibility. By shifting from descriptive cataloging toward platform-based engineering logic, this review provides a translational roadmap for rational fungal EPS design within standardized and application-driven manufacturing frameworks.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13202872/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148016473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Harnessing the thermotolerant methylotroph Bacillus methanolicus for methanol-based synthetic L-proline production.","authors":"Christine Frank, David Virant, Gregor Kosec, Tamara Hoffmann, Oskar Zelder, Max F Felle, Erhard Bremer","doi":"10.1186/s12934-026-03032-8","DOIUrl":"10.1186/s12934-026-03032-8","url":null,"abstract":"<p><strong>Background: </strong>Bacillus methanolicus MGA3 is a thermotolerant methylotroph that utilizes methanol, a renewable C₁ substrate, as its sole carbon and energy source. The strain naturally overproduces and secretes L-glutamate, making it a promising platform for engineering pathways toward L-glutamate-derived amino acids such as L-proline, which has applications in nutrition, stress protection, and industry.</p><p><strong>Results: </strong>Heterologous expression of an osmotic stress-responsive L-proline biosynthetic operon from the mesophile Bacillus licheniformis in the thermotolerant B. methanolicus strain MGA3 did not increase L-proline levels but instead led to accumulation of L-citrulline. This was likely due to heat sensitivity of pyrroline-5-carboxylate reductase (ProH), the last enzyme of the osmoregulatory L-proline biosynthetic route, and metabolic crosstalk between L-proline and L-arginine pathways operating in Bacilli. To overcome these limitations, a synthetic operon containing the native anabolic proBA and proI L-proline biosynthetic genes from B. methanolicus MGA3 was engineered to remove transcriptional T-box regulation and biochemical feedback inhibition of ProB enzyme activity. Expression of this engineered operon enhanced L-proline synthesis and triggered its secretion during methanol-based growth of B. methanolicus MGA3 at 50° C. In fed-batch fermentation with methanol as carbon and energy source, extracellular L-proline levels reached 262 ± 20 mg L⁻¹ after 40 h. During the fermentation process, a stepwise increase in medium osmolarity was observed, likely due to large-scale L-glutamate excretion, which impaired cellular growth.</p><p><strong>Conclusions: </strong>This study links osmolarity dynamics to methanol-based fermentation in B. methanolicus MGA3 and demonstrates its potential as a cell factory for L-proline and L-citrulline production. These findings support further strain optimization for producing value-added amino acids and highlight the relevance of methylotrophic thermophiles in sustainable biotechnology.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"25 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13198045/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148005990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimization of an improved chemically defined medium for high-efficiency expression of glucokinase in Escherichia coli.","authors":"Yuhan Ma, Jiahao Kong, Zongjin Wang, Sitong Chen, Xu Yang, Min Chen, Zhenguo Wen, JianYe Xia","doi":"10.1186/s12934-026-03027-5","DOIUrl":"10.1186/s12934-026-03027-5","url":null,"abstract":"<p><strong>Background: </strong>Recombinant glucokinase (GLK), an important enzyme for blood glucose diagnostics, is commonly prepared in Escherichia coli (E.coli )for laboratory research and related biosynthetic applications. In small-scale laboratory cultivation, complex media are often used because of their convenience and strong growth-supporting capacity, but their ill-defined composition and batch-to-batch variability can compromise reproducibility and increase medium-related costs. Although minimal defined medium (e.g., M9 medium) are generally preferred in scalable E. coli bioprocesses because of their compositional consistency and process controllability, their relatively simple nutrient composition may limit recombinant protein expression performance under laboratory-scale conditions. Therefore, developing an improved chemically defined medium represents a practical strategy to balance expression efficiency, compositional control, and medium cost for recombinant GLK production.</p><p><strong>Results: </strong>To address this, we developed a chemically defined medium including amino acids using high-throughput respiration activity monitoring system (RAMOS) and a high-throughput growth curve analysis system (Growth Profiler 960, GP960), alongside a machine learning-driven iterative optimization system (Machine-learning guided Experimental Trials for Improvement of Systems, METIS). The optimized medium enhanced soluble GLK expression by 33 fold compared to the pre-optimization medium, reaching 74% of the titer obtained in complex media, while reducing medium costs by 74%. Moreover, soluble protein expression per cell increased by 80% compared to the complex medium, lowering the medium usage cost per unit of bacterial protein by 85%. Validation in a 7.5 L bioreactor demonstrated that the optimized medium supported continuous growth to an optical density at 600 nm (OD₆₀₀) of 103, achieving 4-fold and 5.4-fold higher biomass than Luria-Bertina (LB) and M9 media, respectively, with soluble GLK titer reaching 920 mg L^- 1, which exceeded conventional media by more than 10-fold.</p><p><strong>Conclusion: </strong>This study tackles the challenge of suboptimal media in GLK fermentation, offering a cost-effective alternative and a transferable strategy for optimizing fermentation processes for other high-value enzymes.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13491839/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148005908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microbial systems for azo dye biodegradation: enzymatic mechanisms, microbial consortia, and emerging biotechnological strategies.","authors":"Manar K Abd Elnabi, Marwa Eltarahony, Abdullah M El-Badry, Amr Nassrallah, Yehia A-G Mahmoud, Mohamed A Ghazy, Ahmed Kamal, Sameh S Ali","doi":"10.1186/s12934-026-03017-7","DOIUrl":"10.1186/s12934-026-03017-7","url":null,"abstract":"<p><p>Azo dyes are the most widely used class of synthetic colorants in textile and related industries; however, their discharge into natural ecosystems poses severe environmental and human-health concerns due to their xenobiotic structure, toxicity, and resistance to degradation. Traditional physicochemical remediation strategies are often costly and may result in incomplete mineralization and secondary pollution. Microbial systems provide an ecologically compatible and economically viable solution through efficient enzymatic reduction and subsequent mineralization of azo dyes and their degradation intermediates. This review synthesizes current advances in microbial bioremediation, with particular emphasis on the enzymatic mechanisms and metabolic processes involved in azo dye degradation, including the roles of key enzymes such as azoreductases, laccases, and peroxidases. The synergistic performance of microbial consortia, optimization of environmental and nutritional parameters, and the integration of bioelectrochemical systems are also discussed. Recent innovations-including genetic engineering, advanced immobilized biocatalysts, nanobiotechnology, high-performance bioreactors, and artificial-intelligence-driven process optimization-are evaluated for their potential to enhance biodegradation efficiency and operational stability. Finally, the major challenges and future perspectives for developing robust microbial systems capable of efficient detoxification and mineralization of azo dyes in industrial wastewater are highlighted. Overall, this review emphasizes the potential of microbial systems and emerging biotechnological strategies as sustainable solutions for azo dye remediation and environmentally responsible wastewater management.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13307425/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148005940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Expanding the substrate spectrum in engineered Pseudomonas taiwanensis for efficient production of 4-coumarate from lignocellulosic sugars.","authors":"Benedikt Wynands, Sophia Feltes, Nadine Teófilo da Silva, Tino Polen, Nick Wierckx","doi":"10.1186/s12934-026-03014-w","DOIUrl":"10.1186/s12934-026-03014-w","url":null,"abstract":"<p><p>Aromatics are important building blocks for polymers, pharmaceuticals, and advanced materials, but their current production relies on petrochemical processes. Biotechnological de novo production from renewable bio-based feedstocks with microbial cell factories provides a sustainable alternative. In this study, we enhanced 4-coumarate production in Pseudomonas taiwanensis from glucose and glycerol compared to previously published producers. This was achieved through heterologous expression of tyrosine ammonia-lyase (TAL) from Rivularia sp. PCC7116, which debottlenecked the specific deamination of tyrosine. Moreover, deletion of the phosphoenolpyruvate carboxylase-encoding gene ppc further increased the production. Subsequently, the substrate spectrum for efficient aromatics production was expanded to include the abundant pentoses, xylose and arabinose. Heterologous non-oxidative assimilation pathways were integrated into P. taiwanensis GRC3 chassis strains and growth on xylose and arabinose was improved through adaptive laboratory evolution, whole-genome sequencing, and reverse engineering. Optimized catabolic modules were then transferred to producer strains to enhance or enable 4-coumarate production from xylose and arabinose. Notably, the product yield on xylose increased approximately 3.5-fold with the non-oxidative xylose isomerase pathway compared to the oxidative native Weimberg pathway, without compromising yields on glucose. For the final strain, P. taiwanensis GRC3Δ6-TYR2Δppc-REXA-attTn7::P_14f-RpcTAL, product yields were significantly higher on xylose (38.2% (Cmol/Cmol)) and arabinose (39.7% (Cmol/Cmol)) than on glucose (26.0% (Cmol/Cmol)). 4-Coumarate production was characterized on mixtures of glucose, xylose, and arabinose to mimic lignocellulosic hydrolysate feedstocks, with the best reverse-engineered xylose- and arabinose-metabolizing 4-coumarate producer significantly outperforming the reference strain.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13200318/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148005965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Site-directed mutagenesis and semi-rational design to enhance chitinolytic activity of bacterial exochitinase.","authors":"Mati Ullah, Jianda Han, Xiaomei Zhu, Zhongjian Guo, Najumuddin, Muhammad Naeem, Vivian Andoh, Guoqiang Guan, Abebe Bogale, Esmael M Alyami, Ohoud A Alghamdi, Turki M Dawoud, Huayou Chen","doi":"10.1186/s12934-026-03031-9","DOIUrl":"10.1186/s12934-026-03031-9","url":null,"abstract":"<p><p>Chitin, a prevalent biopolymer found in arthropod exoskeletons and fungal cell walls, requires efficient depolymerization to provide bioactive derivatives suitable for agriculture, medicine, and wastewater treatment. Bacterial chitinases, such as the exochitinases produced by Paenibacillus barengoltzii, are potential biocatalysts for chitin recycling; however, they exhibit insufficient activity and stability for industrial use. In this study, Semi-rational engineering and site-directed mutagenesis were employed to enhance catalytic efficiency, resulting in five mutants: M1 (D344Y), M2 (D192Y), M3 (D144Y), M4 (D534G), and M5 (D192A). M3 and M5 significantly increased chitinolytic activity, boosting it by 338% and 276%, respectively, compared to the original enzyme. Further enhancement was achieved by incorporating a chitin-binding domain (CBD), resulting in a six-fold increase in activity with the M35-CBD chimaera. Molecular dynamics (MD) simulations were performed on wild-type, M3, and M5 variations to elucidate the structural basis for these enhancements. M3 (D144Y) exhibited greater structural stability, less RMSD fluctuations, and an improved hydrogen bond network in the substrate-binding region. Notably, enhanced π-stacking interactions facilitated by solvent-exposed aromatic residues, including tryptophan, improved substrate affinity. Unlike the wild-type enzyme, the produced mutants exhibited reduced conformational mobility alongside increased substrate interaction. The results demonstrate the efficacy of targeted mutagenesis and domain engineering in creating stable chitinases for industrial and environmental biotechnology applications.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13393625/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147988251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Conversion of CO₂ into valuable products: engineering the PirC-PGAM switch in cyanobacteria to direct carbon flux into desired products.","authors":"Nathalie Sofie Becker, Franziska Hufnagel, Paul Bolay, Kevin Otec, Tim Orthwein, Andreas Kulik, Phillipp Fink, Claudius Lenz, Pia Lindberg, Karl Forchhammer, Stephan Klähn","doi":"10.1186/s12934-026-03033-7","DOIUrl":"10.1186/s12934-026-03033-7","url":null,"abstract":"<p><strong>Background: </strong>In response to rising CO₂ emissions driving global warming, there is an urgent need for a transition toward a sustainable bioeconomy. Photo-biotechnological processes based on oxygenic photosynthesis hold high potential for achieving CO₂ neutrality and in this regard, cyanobacteria have emerged as promising biocatalysts. Rational metabolic engineering of cyanobacteria depends on a thorough understanding of regulatory mechanisms governing primary metabolism, because native metabolic flux through specific pathways and, consequently, the formation of target products can be limited. Recent insights have identified a key regulatory node at the 2,3-bisphosphogylcerate-independent phosphoglycerate mutase (PGAM) reaction, where the metabolic flux from newly fixed carbon is redirected from the Calvin-Benson-Bassham (CBB) cycle towards lower glycolysis. This metabolic valve is controlled by the small inhibitor protein PirC, whose binding to PGAM is determined by the central signal transduction protein PII.</p><p><strong>Results: </strong>In this study, we exploit the PirC-PGAM interaction as a novel target for regulatory metabolic engineering in the model cyanobacterium Synechocystis sp. PCC 6803 (Synechocystis). Chassis strains with engineered control of PGAM, defined as PGAM-ON or PGAM-OFF states, were generated using two complementary approaches: tuning pgam gene expression and modulating PirC abundance to regulate PGAM activity. The effectiveness of this regulatory engineering strategy was demonstrated by redirecting carbon flux toward two representative, naturally occurring products: sucrose, produced via gluconeogenesis fueled by the Calvin-Benson-Bassham (CBB) cycle, and succinate, an intermediate of the tricarboxylic acid (TCA) cycle. Narrowing the PGAM valve resulted in a threefold increase in sucrose accumulation. In contrast, opening the PGAM valve by relieving PGAM inhibition through pirC deletion or separate pgam overexpression resulted in up to an 18-fold increase in succinate excretion. Furthermore, similar genetic configurations were applied to enhance production of a heterologous compound, isoprene, derived from pyruvate.</p><p><strong>Conclusions: </strong>This study establishes the PGAM valve as a tunable control point for the rational re-direction of carbon flux in Synechocystis and highlights small regulatory proteins as powerful targets for metabolic engineering. Together, these findings provide proof of concept for an advanced level of molecular engineering in cyanobacteria and to fully harness their biocatalytic potential in future photosynthesis-driven biotechnological applications.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13192157/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147982144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Utilization of sugarcane bagasse waste by Aspergillus welwitchiae SVUAw9 for production, purification, and characterization of cold-active xylanase under solid-state fermentation conditions.","authors":"Asmaa S Yassein, Walaa S Ahmed, Ahmed H Elsayed, Mohamed A Hussein, Osama A M Al-Bedak","doi":"10.1186/s12934-026-03025-7","DOIUrl":"10.1186/s12934-026-03025-7","url":null,"abstract":"<p><p>Aspergillus welwitschiae strain SVUAw9 was isolated from sugarcane bagasse and identified by the sequencing of the calmodulin (CaM) gene, was found to exhibit substantial cold-active xylanase activity in this study. Under solid-state fermentation conditions, the strain can utilize a range of agro-industrial residues as substrates to produce cold-active xylanase. After 14 days at pH 7 and 10 °C using ammonium chloride as the nitrogen source, sugarcane bagasse was the most productive substrate, generating 106.93 ± 12.1 U/gram dry substrate (gds), followed by bean straw, corn cob, and date palm leaves which produced 57.82 ± 8.27, 57.75 ± 7.44, and 38.87 ± 6.15 U/gds, respectively. Conversely, the substrate exhibiting the lowest production was rice husk, producing 29.32 ± 4.88 U/gds. Using Trilite MC 08 and Sephacryl S-200 columns, the xylanase was purified 75.87 times, yielding a single band at approximately 71 kDa. At pH 4.0 and 30 °C, the maximum activity of 156.46 ± 12 U/mg was achieved. Co(NO₃)₂, MnSO₄, and NiSO₄ markedly enhanced enzyme activity, resulting in residual activity increases of 152.94 ± 11.54%, 152.94 ± 9.58%, and 134.12 ± ठर 7.66%, respectively, with specific activities of 239.3 ± 18, 239.3 ± 15, and 209.84 ± 12 U/mg. Km and Vmax for the pure xylanase were determined as 0.1 ± 0.005 mg/mL and 144.9 ± 7.14 µmol/min, respectively. The purified xylanase could degrade oat spelt xylan, corn cob xylan, xylan, Birchwood xylan, maize stalk xylan, carboxymethyl cellulose (CMC), beechwood and microcrystalline cellulose (MCC), resulting in activities of 156 ± 12, 108 ± 7, 82 ± 6, 79 ± 5, 62 ± 4, 22 ± 1.5, and 38 ± 3 U/mg, respectively.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13188304/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147973978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biosensor-driven evolution and metabolic engineering of an Escherichia coli cell factory for L-tryptophan production.","authors":"Rongshuai Zhu, Zhenqiang Zhao, Weijun Shao, Jin Han, Jiajia You, Xuewei Pan, Minglong Shao, Zhiming Rao","doi":"10.1186/s12934-026-03028-4","DOIUrl":"10.1186/s12934-026-03028-4","url":null,"abstract":"<p><p>L-Tryptophan is an important aromatic amino acid with wide applications across the food, pharmaceutical, and feed industries. However, its efficient microbial production remains challenging due to complex metabolic networks and multi-level feedback regulation. In this study, we constructed a highly efficient Escherichia coli cell factory for L-tryptophan biosynthesis by combining systematic metabolic engineering with high-throughput screening. Initially, a tnaC-based biosensor was developed and coupled with atmospheric and room temperature plasma (ARTP) mutagenesis to isolate high-performance chassis strains. Central carbon metabolism was subsequently reprogrammed to minimize carbon loss and channel metabolic fluxes toward essential precursors, phosphoenolpyruvate (PEP) and erythrose-4-phosphate (E4P). To further alleviate pathway bottlenecks, promoter engineering was utilized to balance the intracellular supplies of L-glutamine, L-serine, and phosphoribosyl pyrophosphate (PRPP). This targeted intervention yielded a 21.61% increase in L-tryptophan accumulation. Product transport systems were then engineered to enhance extracellular secretion and mitigate intracellular toxicity. Following the optimization of inoculum size and feeding strategies in a 5 L bioreactor, the final engineered strain (W-24) produced 50.83 g/L of L-tryptophan within 40 h, achieving a yield of 0.185 g/g glucose. This multi-modular engineering framework establishes a robust platform for L-tryptophan biosynthesis and provides a scalable strategy for the industrial production of other valuable aromatic compounds.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13361465/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147973923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}