Microbial Cell Factories最新文献

{"title":"First evidence of keratinolytic activity in Simplicillium aogashimaense isolated from wool-pellet-amended soil.","authors":"Clémentine Isembart, Zoé Bruchon, Jean-Michel Yao, Boris Zimmermann, Cristian Bolaño Losada, Achim Kohler, Paige Heavyside, Volha Shapaval","doi":"10.1186/s12934-026-03066-y","DOIUrl":"10.1186/s12934-026-03066-y","url":null,"abstract":"<p><strong>Background: </strong>Keratin-rich waste such as wool and feather wastes are generated in large quantities worldwide and remain difficult to valorize due to the structural resilience of keratin, that is reinforced by disulfide bonds. Microbial degradation offers a sustainable approach for converting these wastes into value-added products. In this study, keratin-degrading fungi were isolated from garden soils amended with wool pellets used as organic fertilizer. Three fungal strains showing keratinolytic activity were selected based on halo formation on keratin-containing agar media. Among them, Simplicillium aogashimaense was chosen for detailed characterization due to its non-pathogenic status, limited representation in the literature, and the absence of previously reported proteolytic or keratinolytic activity.</p><p><strong>Results: </strong>Feather meal degradation by S. aogashimaense was investigated during 12 days of submerged cultivation. The strain demonstrated strong keratinolytic potential, achieving up to 80% feather meal mass reduction. Biochemical analysis of the resulting hydrolysates, including protease activity, elemental composition, amino acid profiles, ammonium and sulfur concentrations, pH dynamics, and overall biochemical profile, revealed a multiphasic degradation pattern. The initial phase (days 1-3) was characterized by rapid feather breakdown, elevated protease activity, ammonium release, and preferential liberation of surface-accessible amino acids, indicating efficient enzymatic attack on exposed keratin domains. The intermediate phase (days 4-6) during which general protease activity declines along with the fungal biomass. This period is likely to correspond to a shift from feather degradation to assimilation and intracellular metabolism. During the final phase (days 7-12), measured parameters stabilized, consistent with maximal substrate degradation and subsequent assimilation of soluble hydrolysis products by the fungus.</p><p><strong>Conclusions: </strong>This study provides the first evidence that S. aogashimaense exhibits keratin-degrading capability, identifying it as a previously unrecognized keratinolytic fungal species. These findings broaden current understanding of fungal keratin degradation and highlight the potential of S. aogashimaense for sustainable bioconversion of feather waste and other keratin-rich residues. Further optimization and mechanistic investigation of its enzymatic system may support future biotechnological applications in waste valorization.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13587383/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148456480","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":"Exogenous glycine promoted the overproduction of extracellular pigments of Monascus purpureus S109 in submerged fermentation.","authors":"Sixu Lin, Xue Yang, Junyao Wang, Bing Li, Qinghua Yu, Yuning Zhang, Jialin Wu, Xuerui Yan","doi":"10.1186/s12934-026-03065-z","DOIUrl":"10.1186/s12934-026-03065-z","url":null,"abstract":"<p><p>The content of extracellular Monascus pigments (eMPs), which has strong functional activity and stability, was improved by adding glycine in previous research. This study systematically elucidated the effects of different glycine concentrations on Monascus purpureus (M. purpureus) S109 eMPs production at both the membrane physiological level and the molecular level of pigment secretion-related gene expression. By measuring the biomass, fatty acid, relative conductivity, fluorescence intensity of tyrosine and tryptophan, membrane potential and ion concentration, coenzyme content, and eMPs content, it was found that 2 g/L glycine could significantly enhance cell membrane fluidity and permeability, and promote the production of eMPs, with their content increasing from 85.82 U/mL to 384.88 U/mL. Under this condition, apart from the negative regulator MrpigI, and the MrpigH directly involved in yellow pigment synthesis, which were down-regulated, all other genes associated with the pigment biosynthesis pathway were significantly up-regulated. Furthermore, the expression of MrpigL and MrpigP genes involved in pigment secretion was significantly up-regulated by 2.8-fold and 10.9-fold, respectively. This study demonstrates that glycine promotes eMPs secretion through modulation of membrane physiological properties and modulation of secretion-related gene expression.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13647656/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148448096","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":"Discovery of a dimeric isopimarane derivative by reexploring a labdane-related diterpenoid biosynthetic gene cluster in Aspergillus nidulans.","authors":"Shu-Yi Lin, Cory B Jenkinson, Quoc-Dung Tran Huynh, C Elizabeth Oakley, Ching-Kuo Lee, Haiyao Ma, Berl R Oakley, Clay C C Wang","doi":"10.1186/s12934-026-03056-0","DOIUrl":"10.1186/s12934-026-03056-0","url":null,"abstract":"<p><strong>Background: </strong>Diterpenes derived from geranylgeranyl diphosphate include the pimarane family, a class of tricyclic diterpenoids widely distributed in plants and fungi. Previous studies on Aspergillus nidulans identified a biosynthetic gene cluster containing a diterpene cyclase that produces ent-pimara-8(14),15-diene, whereas subsequent biochemical analysis suggested the enzyme instead generates an isopimarane scaffold.</p><p><strong>Results: </strong>In this study, we have reexplored this diterpene biosynthetic pathway by using a multi-cluster deletion strain to reduce the metabolite background and a modified version of the highly inducible alcA promoter system to drive expression of a transcription factor in the cluster that includes the diterpene cyclase gene. The transcription factor, in turn, drives expression of all the genes of the cluster. Induction of expression resulted in production of compounds not seen with prior methods. Liquid chromatography-mass spectrometry (LC-MS) and Nuclear magnetic resonance (NMR) analysis has enabled us to identify dipleosmarane (3), a new dimeric isopimarane derivative, together with six known isopimarane diterpenoids (1, 2, 4a, 4b, 5, 6). Gene deletion experiments targeting the terpene cyclase (pbcA) and geranylgeranyl pyrophosphate synthase (pbcB) confirmed that these metabolites originate from this cluster.</p><p><strong>Conclusions: </strong>Our findings support the conclusion that the A. nidulans diterpene cyclase primarily synthesizes an isopimarane scaffold rather than an ent-pimarane derivative. Furthermore, the combination of transcription factor activation and a multi-cluster deletion background proved effective for revealing previously undetected metabolites from this pathway. These findings provide new insight into fungal diterpenoid biosynthesis and establish a useful platform for further genetic dissection and engineering of isopimarane biosynthetic pathways in Aspergillus.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13644022/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148436918","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":"Investigating the role of F_OF₁ ATPase in Zymomonas mobilis through deletion of its F_O and F₁ subcomplexes.","authors":"Gerrich Behrendt, Reinis Rutkis, Uldis Kalnenieks, Katja Bettenbrock","doi":"10.1186/s12934-026-03059-x","DOIUrl":"10.1186/s12934-026-03059-x","url":null,"abstract":"<p><p>Zymomonas mobilis has a typical F_OF₁ ATPase, yet does not exhibit oxidative phosphorylation. In order to investigate the function of the ATPase we sought to delete the F_O and the F₁ subcomplexes, respectively. Clean mutants could be obtained after selection under aerobic conditions. Growth analysis of the mutants showed that they strictly require oxygen for growth and that the oxygen supply is a factor determining maximal growth rate. This is contrary to the wild type, which grows fastest under anaerobic conditions. In the mutant strains, ethanol remains the main catabolic product; however glucose consumption rates are reduced, and the mutants show a higher sensitivity to low medium pH. Compared to the wild type, the mutants show an increased biomass yield. Our data support the previously proposed regulatory role of the F_OF₁ ATPase in controlling glycolytic flux, and indicate that the F_OF₁ ATPase plays an important role in expelling protons from the cytoplasm. In the mutants, this function is taken over by the electron transport chain in the presence of oxygen.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13366798/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148436964","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":"Integrated transcriptomic and DNA methylomic analysis of Yarrowia lipolytica in response to La(III)/Ce(III) stress.","authors":"Jingqi Liu, Huangfeng Qiu, Donghua Tan, Yuting Liang, Haiyan Wu, Yu Yang, Hongbo Zhao","doi":"10.1186/s12934-026-03041-7","DOIUrl":"10.1186/s12934-026-03041-7","url":null,"abstract":"<p><p>Rare earth elements (REEs), as strategic resources, cause severe pollution and ecological degradation through chemical leaching processes. Bioremediation technology offers an efficient green alternative for REE recovery from wastewater. This study investigated Yarrowia lipolytica to elucidate its efficient adsorption mechanisms and stress adaptation towards La(III)/Ce(III). Phenotypic analysis revealed that the strain enhances adsorption capacity for La(III)/ Ce(III) by increasing specific surface area through dimorphic transition. Under optimal conditions, adsorption rates reached 84.33% for La(III) and 87.21% for Ce(III). Adsorption kinetics followed a pseudo-second-order model (indicating chemisorption dominance), and isotherms conformed to the Langmuir model (suggesting monolayer adsorption). FTIR and XPS analyses identified cell surface -OH groups as key active sites, directly capturing REE ions via complexation. Integrated transcriptomic and DNA methylomic analyses uncovered interaction mechanisms and stress responses: La(III) exposure inhibited glycolysis/TCA cycle genes while activating peroxisome pathways (antioxidant defense) and ABC transporters (ion efflux). Ce(III) exposure specifically suppressed amino acid metabolism (e.g., glutamate pathway). Whole-genome methylation levels decreased significantly with preferential methylation in CHH contexts. 10 (La(III)) and 4 (Ce(III)) were identified differentially expressed genes accompanied by altered methylation levels, demonstrating DNA methylation-mediated regulation of La(III)/Ce(III) resistance genes. This study lays a theoretical foundation for bioremediation of REE pollution.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13640256/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148430814","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":"Development and optimization of a glycerol-based fed-batch strategy for the production of peroxidases with Komagataella phaffii under the P_DF promoter.","authors":"Christian Mathis Wagner, Katharina Schwartz, Hannah Czech, Ines Lamping, Xavier Garcia-Ortega, Anton Glieder, Wolfgang Wiechert, Marco Oldiges","doi":"10.1186/s12934-026-03055-1","DOIUrl":"10.1186/s12934-026-03055-1","url":null,"abstract":"<p><strong>Background: </strong>Unsaturated polyester resins are commonly polymerized using cobalt-based siccatives. However, growing health concerns and increasing demand for cobalt highlight the need for more sustainable alternatives. Heterologously produced peroxidases, produced through secretory expression in Komagataella phaffii (K. phaffii, previously classified as Pichi a pastoris), represent a promising substitute for cobalt in such applications. To tailor the bioprocess for the production of peroxidases, dedicated bioprocess development and optimization are required. Rather than relying on methanol induction, the process should aim to achieve production via glycerol derepression under the control of the P_DF promoter. This strategy mitigates the safety risks and metabolic stress associated with methanol utilization.</p><p><strong>Results: </strong>This study presents the development and optimization of a three-phase bioprocess for peroxidase production in K. phaffii under the P_DF promoter, induced via glycerol derepression. The process comprises a batch growth phase, a growth and induction fed-batch phase and a second fed-batch phase for product formation. Exponential feeding at 50% of the maximum specific growth rate (µ_max) was identified as the optimum, balancing growth, induction and productivity. During the production phase, a glycerol feed at 20% of the maximum uptake rate (q_Smax) and a duration of up to 96 h yielded the best results. The final optimized process achieved a titer of 12.36 U*mL^-1, a yield of 46.31 U*g^-1, and a space-time yield of 0.081 U*mL^-1*h^-1, which clearly outcompeted the methanol reference process by a factor of 13.4. Strikingly, the use of crude glycerol further improved performance by approximately 10%, demonstrating process robustness. Overall, this bioprocess enables efficient and sustainable peroxidase production, offering a viable alternative to cobalt-based catalysts in polyester resin curing.</p><p><strong>Conclusions: </strong>This work demonstrates the feasibility of a robust, methanol-free bioprocess for peroxidase production in K. phaffii, driven by glycerol derepression under the P_DF promoter. The optimized process achieves high titers and yields, maintains performance even with crude glycerol, and could support sustainable replacement of cobalt-based siccatives in industrial polymerization. These findings provide a valuable foundation for advancing biocatalytic solutions in green manufacturing.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"25 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13352833/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148422504","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":"Metabolic engineering of Synechocystis sp. PCC 6803 for olivetolic acid production.","authors":"E-Bin Gao, Wenrui Ji, Yangjie Zhu, Junhua Wu","doi":"10.1186/s12934-026-03058-y","DOIUrl":"10.1186/s12934-026-03058-y","url":null,"abstract":"<p><p>Olivetolic acid (OLA), the critical aromatic precursor for plant-derived cannabinoids, conventionally relies on resource-intensive plant extraction or complex chemical synthesis. This study establishes an environmentally friendly biosynthetic platform by genetically engineering the model cyanobacterium Synechocystis sp. PCC 6803. We constructed the heterologous OLA pathway by co-expressing plant-derived tetraketide synthase (TKS), olivetolic acid cyclase (OAC), and acyl-activating enzyme 1 (AAE1). Through cultivation supplemented with sodium hexanoate, successful biosynthesis of OLA was achieved within this photosynthetic host. To overcome metabolic bottlenecks, the pathway was further optimized using the robust P_cpc560 promoter coupled with carbon sink redirection strategy. Disruption of the primary glycogen storage sink (ΔglgC) combined with the overexpression of the anaplerotic malic enzyme gene (maeB) significantly enhanced the specific OLA yield. Notably, while continuous aeration with 5% CO₂ drastically accelerated cell growth and prolonged the cultivation period, it simultaneously led to a severe decrease in the specific OLA yield. This work demonstrates the feasibility of utilizing a cyanobacterial chassis for precursor-directed OLA biosynthesis, establishing a foundational blueprint for the sustainable manufacturing of cannabinoid-related metabolites.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13628793/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148412278","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":"Metabolic engineering of Escherichia coli strains for the in vivo phosphorylase-mediated synthesis of disaccharides.","authors":"Pietro Tedesco, Julien Durand, Laurence Tarquis, Gabrielle Potocki-Veronese, Fabien Létisse","doi":"10.1186/s12934-026-03051-5","DOIUrl":"10.1186/s12934-026-03051-5","url":null,"abstract":"<p><strong>Background: </strong>Enzymatic synthesis of rare disaccharides by reverse-phosphorolysis is a potentially sustainable route to produce high-value glycosides for human health and nutrition. In vivo synthesis using microorganisms expressing recombinant glycoside phosphorylases is an attractive strategy, as it may overcome key limitations associated with conventional chemical and enzymatic approaches. However, successful implementation requires dedicated metabolic chassis enabling efficient precursor supply and carbon flux redirection. In Escherichia coli, inactivation of the phosphotransferase system (PTS) combined with deletion of pfkA constitutes a promising strategy to decouple sugar uptake from their concomitant phosphorylation, promote the accumulation of key sugar phosphates, and enable reverse biosynthetic pathways for oligosaccharide production.</p><p><strong>Results: </strong>We first established β-1,2-mannobiose production as a proof of concept. The expression of heterologous permease GalP restored the growth on mannose in a PTS⁻ background and allowed mannose into the reverse biosynthetic pathway. Deletion of pfkA, which promotes intracellular accumulation of glucose 1-phosphate (G1P) and mannose 1-phosphate (M1P), combined with the expression of a β-1,2-mannoside-phosphorylase, enabled the direct synthesis of β-1,2-mannobiose from mannose. The pfkA deletion significantly increased product titers (> 0.6 g·L⁻¹) and yields (up to 9% g/g mannose), reflecting an efficient redistribution of carbon fluxes toward disaccharide formation. Furthermore, mixed-substrate cultures using glycerol as the carbon and energy source, together with additional metabolic engineering, enabled partial growth-production decoupling and redirected mannose utilization primarily toward product synthesis, achieving yields of up to 60%. The same metabolic chassis was further employed for the production of β-1,4-mannobiose and laminaribiose through the expression of a β-mannoside-phosphorylase and a laminaribiose-phosphorylase, using mannose and glucose as substrates, respectively.</p><p><strong>Conclusion: </strong>Here, we report the metabolic engineering of Escherichia coli for in vivo production of oligosaccharides with different glycosidic linkages from hexose sugars. These results demonstrate the modularity and efficiency of the proposed platform for fermentative production of non-conventional oligosaccharides and expand the scope of metabolic engineering strategies for glycoside biosynthesis.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13625282/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148405176","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":"Genomically integrated orthogonal translation system in Escherichia coli enables production of functional modified [NiFe]-hydrogenases.","authors":"Qin Fan, Stevanie Stevanie, Stefan Frielingsdorf, Peter Neubauer, Oliver Lenz, Matthias Gimpel","doi":"10.1186/s12934-026-03057-z","DOIUrl":"10.1186/s12934-026-03057-z","url":null,"abstract":"<p><p>The functional diversification of O₂-tolerant [NiFe]-hydrogenases using orthogonal translation systems (OTSs) offers a promising strategy for developing advanced biocatalysts and biohybrid energy platforms. However, plasmid-based OTSs frequently impose metabolic burdens and suffer from plasmid instability during fermentation, particularly when co-produced with complex metalloenzymes. To overcome these bioprocess limitations, we employed CRISPR/Cas9-mediated genome editing to integrate a psychrophilic pyrrolysyl-tRNA synthetase/tRNA pair into the Escherichia coli BL21 genome. The resulting strain provided a plasmid-free orthogonal translation background that supported amber suppression-mediated expression of the regulatory [NiFe]-hydrogenase (RH) of Cupriavidus necator. Using this genomically integrated OTS, we achieved the production of a full-length, catalytically active RH variant. Our results demonstrate that chromosomal OTS is compatible with the efficient production and maturation of complex metalloenzymes. The present work lays the groundwork for the bio-orthogonal engineering of hydrogenases and related hybrid biocatalysts.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13340272/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148397181","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":"The transcriptional response to environmental alkalization involves both Komagataella phaffii Pho4 transcription factors.","authors":"Marcel Albacar, Antonio Casamayor, Rui Wang, Joaquín Ariño, Asier González","doi":"10.1186/s12934-026-03054-2","DOIUrl":"10.1186/s12934-026-03054-2","url":null,"abstract":"<p><strong>Background: </strong>Pho4 is a fungal transcription factor essential for the response to phosphate (Pi) starvation in many fungi and is usually encoded by a single gene. However, we recently reported that the methylotrophic yeast Komagataella phaffii encodes two functional Pho4 proteins, named Pho4(A) and Pho4(B), and that only Pho4(B) was required for the transcriptional response to Pi limitation. Pho4 is also important in many yeasts for adaptation to an alkaline environment. We evaluate here the participation of Pho4(A) and Pho4(B) in the transcriptional response to alkaline pH.</p><p><strong>Results: </strong>We show that the expression of nearly one-hundred genes is altered in a pho4(A) pho(B) mutant. In contrast to Pi starvation, Pho4(A) becomes important under high pH stress for the short-time expression of genes required for Pi homeostasis, such as PHO89, VTC1, VTC2, VTC4 and PHO4(B), suggesting that both transcription factors respond to different signals. Integration of the transcriptional data with that obtained from crz1 or rim101 mutants shows that nearly 80 genes are regulated by at least two of these transcription factors. Thus, we show that induction of PHO89 by Pi starvation or high pH is fully abolished in both double pho4(A) pho4(B) and single rim101 mutants, and that mutation of CRZ1 and RIM101 partially eliminates the sensitivity to high pH of the pho4(A) pho4(B) strain, revealing unexpected genetic interactions between these mutations. Finally, we identify an alkali-sensitive region in the PHO89 promoter and demonstrate that its duplication further increases the promoter's response to alkalinization.</p><p><strong>Conclusions: </strong>The transcription factor Pho4(A) is not required for the transcriptional response to Pi starvation, but it contributes to the response to alkalinization. Gene expression remodeling upon alkalinization in K. phaffii is controlled by diverse signaling pathways, including Pho4, Crz1 and Rim101 as well as other components still to uncover. Detailed knowledge of the signaling mechanisms triggered upon alkalinization and promoter mapping of the genes responsive to high pH will be useful tools for the generation of alkaline pH-regulated hybrid synthetic promoters in K. phaffii with improved features.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":" ","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13613856/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148388098","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}