Microbial Cell Factories最新文献

{"title":"Enhancing Bacillus cereus antibacterial ability through improved cofactor supply.","authors":"Yinbiao Xu, Jiasong Wu, Tingting Yuan, Zongda Chen, Danqi Feng, Peizhao Yang, Liaoyuan Han, Luyang Geng, Jinyuan Hu, Gang Wang","doi":"10.1186/s12934-025-02666-4","DOIUrl":"10.1186/s12934-025-02666-4","url":null,"abstract":"<p><p>Bacillus cereus 0-9 is a biocontrol microorganism that antagonizes Gram-positive bacteria and pathogenic fungi, such as Staphylococcus aureus and Gaeumannomyces graminis, through the secretion of antimicrobial peptides. However, its low antibacterial activity limits its biocontrol application. In this study, a significant enhancement in antibacterial activity against S. aureus was achieved by overexpressing glucose dehydrogenase from Bacillus subtilis (BsGDH) in B. cereus 0-9, expanding the activity from 6.98 to 11.59 U/mL, representing a 66% improvement. To further improve its biocontrol capability, we aimed to improve the catalytic efficiency of BsGDH by screening 11 low-conserved residues in the protein's second-shell via conservation analysis and molecular docking. Following three rounds of saturation mutagenesis, the specific enzyme activity and K_cat/K_m value of the variant N97F/N192S/E198G reached to 289.74 U/mg and 4.95 µM⁻¹·min⁻¹, representing 5.66 and 11.38 times greater than that of the wild-type BsGDH, respectively. Molecular docking suggested that residues Gly94, Gly14, and Ile191 form a triangular region enhancing substrate affinity and enzymatic activity. Furthermore, the Root Mean Square Fluctuation analysis from molecular dynamics showed significant conformational changes in five regions of the mutants (α2 helix, α3 helix, α5 helix + β4 sheet, α8 helix + β5 sheet, and α13-14 helix), increasing the flexibility of the active pocket. Ultimately, the antibacterial activity of B. cereus 0-9 expressing N97F/N192S/E198G reached 22.79 U/mL, 2.26 times higher than that of B. cereus 0-9. This study offers a promising candidate for enhancing NAD(P)⁺ metabolic cycling and antimicrobial peptide synthesis in cells for industrial applications.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"24 1","pages":"52"},"PeriodicalIF":4.3,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11887302/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143573480","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":"Characterization and optimization of mnn11Δ-mediated enhancement in heterologous protein production in Kluyveromyces marxianus.","authors":"Shihao Zhou, Pingping Wu, Haiyan Ren, Jungang Zhou, Yao Yu, Hong Lu","doi":"10.1186/s12934-025-02676-2","DOIUrl":"10.1186/s12934-025-02676-2","url":null,"abstract":"<p><strong>Background: </strong>N-glycosylation is a prevalent post-translational modification in eukaryotes, essential for regulating protein secretion. In Saccharomyces cerevisiae, glycosylation mutants have been shown to enhance the secretion of heterologous glycosylated proteins. However, whether these mutants can also increase the secretion of non-glycosylated proteins and whether the growth defects associated with glycosylation mutations can be mitigated remains unclear. This study aimed to characterize and optimize enhanced secretory expression in the promising yeast host Kluyveromyces marxianus by deleting MNN11, which encodes a subunit of the mannose polymerase II complex responsible for elongating α-1,6-linked mannose chains.</p><p><strong>Results: </strong>Compared to wild-type cells, the mnn11Δ cells significantly increased the secretion activities of four glycosylated enzymes and three non-glycosylated enzymes in flasks, with increases ranging from 29 to 668%. Transcriptomic analysis of mnn11Δ mutant revealed upregulation of genes related to essential protein secretion processes, including vesicle coating and tethering, protein folding, translocation, and glycosylation. Additionally, genes involved in vacuolar amino acid transport and amino acid biosynthesis were upregulated, suggesting an amino acid shortage, which might contribute to the observed severe growth defect of the mnn11Δ mutant in a synthetic medium with inorganic nitrogen. Supplementation of the synthetic medium with amino acids or low concentrations of yeast extract alleviated this growth defect, reducing the specific growth rate difference between wild-type strain and mnn11Δ cells from 65% to as little as 2%. During high-density fermentation, the addition of 0.5% yeast extract substantially reduced the lag phase of mnn11Δ mutants and increased the secretory activities of α-galactosidase, endoxylanase, and β-glucanase, by 11%, 18%, and 36%, respectively, compared to mnn11Δ mutant grown without yeast extract.</p><p><strong>Conclusion: </strong>In K. marxianus, deletion of MNN11 enhances the secretion of both glycosylated and non-glycosylated proteins by improving key protein secretion processes. The growth defect in the mnn11Δ mutant is closely tied to insufficient amino acid supply. Supplementing the synthetic medium with low concentrations of organic nitrogen sources effectively alleviates this growth defect and enhances secretory expression. This strategy could be applied to optimize the expression of other glycosylation mutants.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"24 1","pages":"50"},"PeriodicalIF":4.3,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11877904/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143542442","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":"Enhanced thermostability of nattokinase by rational design of disulfide bond.","authors":"Kongfang Yu, Liangqi Chen, Yaolei Tang, Aixia Ma, Wenhui Zhu, Hong Wang, Xiyu Tang, Yuan Li, Jinyao Li","doi":"10.1186/s12934-025-02681-5","DOIUrl":"10.1186/s12934-025-02681-5","url":null,"abstract":"<p><p>Nattokinase, the thrombolytically active substance in the health food natto, nevertheless, its lower thermostability restricts its use in food and pharmaceutical applications. In this study, two heat-resistant variants of nattokinase, designated 50-109 (M1) and 15-271 (M2), were successfully obtained by introducing a disulfide bonding strategy. Their half-lives at 55℃ were found to be 2.50-fold and 5.17-fold higher, respectively, than that of the wild type. Furthermore, the specific enzyme activities of the variants, M1 and M2, were also increased by 2.37 and 1.66-fold, respectively. Meanwhile, the combination of two mutants increased the thermostability of nattokinase by 8.0-fold. Bioinformatics analyses indicated that the enhanced thermostability of the M1 and M2 variants was due to the increased rigidity and structural contraction of the overall structure. Finally, the fermentation process of mutant M1 was optimized to increase the expression of nattokinase. Study provides substantial molecular and theoretical support for the industrial production and application of nattokinase.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"24 1","pages":"51"},"PeriodicalIF":4.3,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11877946/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143542443","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":"Improving activity of GenB3 and GenB4 in gentamicin dideoxygenation biosynthesis by semi-rational engineering.","authors":"Hang Zhai, Lihua Yang, Qi Ye, Zhijun Kong, Jiye Pei, Yuan Ji, Botong Liu, Xiaotang Chen, Tingting Tian, Xianpu Ni, Huanzhang Xia, Shumin Zhang","doi":"10.1186/s12934-025-02678-0","DOIUrl":"10.1186/s12934-025-02678-0","url":null,"abstract":"<p><strong>Background: </strong>Aminoglycoside antibiotics continue to play an indispensable role in clinical antibacterial agents. However, the protection and deprotection procedures in the chemical pathways of semi-synthetic antibiotics are long, atom- and step-inefficient, which severely hampers the development of novel AGs.</p><p><strong>Results: </strong>Here, GenB3 and GenB4 are employed to synthesize sisomicin, Oxo-verdamicin, Oxo-gentamicin C1a, and Oxo-gentamicin C2a. Subsequently, a semi-rational strategy is applied to enhance the activities of GenB3 and GenB4. The activity of GenB3^M1 (Q270N) towards JI-20A-P is 1.74 times higher than that of GenB3^WT. Similarly, the activity of GenB3^M2 (L361C/A412T/Q270N) towards JI-20Ba-P is 1.34 times higher than that of GenB3^WT. The activity of GenB4^M1 (L356C) towards sisomicin is 1.51 times higher than that of GenB4^WT, while GenB4^M2 (L356C/A407T/Q265N) towards verdamicin C2a is 1.34 times higher than that of GenB4^WT. Furthermore, the beneficial effects of these mutants have been validated in engineered strains. Molecular dynamics simulations indicate that GenB3^M1 establishes a hydrogen bond network in the active center, while GenB4^M1 reduces the distance between K238 and the reaction center. It is also noted that the GenB3^M2 exhibits a synergistic effect specifically on JI-20Ba-P, as the C6'-CH₃ group stabilization restricts the movement of the substrate, which contrasts with JI-20A-P.</p><p><strong>Conclusion: </strong>Our results not only lay the foundation for the mild and efficient synthesis of C6'-modified AGs analogues but also serve as a reference for synthesizing additional single components in M. echinospora by further enhancing the dideoxygenation process.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"24 1","pages":"49"},"PeriodicalIF":4.3,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11869428/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143523973","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":"Hyper-porous encapsulation of microbes for whole cell biocatalysis and biomanufacturing.","authors":"Jingyi Zhang, Keziah Chang, Joyce Tay, Elaine Tiong, Elena Heng, Theresa Seah, Yi Wee Lim, Guangrong Peh, Yee Hwee Lim, Fong Tian Wong, Cyrus W Beh","doi":"10.1186/s12934-025-02675-3","DOIUrl":"10.1186/s12934-025-02675-3","url":null,"abstract":"<p><p>Biocatalysis using whole cell biotransformation presents an alternative approach to producing complex molecules when compared to traditional synthetic chemical processes. This method offers several advantages, including scalability, self-contained co-factor recycling systems, the use of cost-effective raw materials, and reduced purification costs. Notably, biotransformation using microbial consortia provides benefits over monocultures by enhancing biosynthesis efficiency and productivity through division of labor and a reduction in metabolic burden. However, reliably controlling microbial cell populations within a consortium remains a significant challenge. In this work, we address this challenge through mechanical constraints. We describe the encapsulation and immobilization of cells in a hyper-porous hydrogel block, using methods and materials that are designed to be amenable to industrial scale-up. The porosity of the block provides ample nutrient access to ensure good cell viability, while the mechanical properties of the hydrogel matrix were optimized for Escherichia coli encapsulation, effectively limiting their proliferation while sustaining recombinant protein production. We also demonstrated the potential of this method for achieving stable co-cultivation of microbes by maintaining two different microbial strains spatially in a single porous hydrogel block. Finally, we successfully applied encapsulation to enable biotransformation in a mixed culture. Unlike its non-encapsulated counterpart, encapsulated E. coli expressing RadH halogenase achieved halogenation of the genistein substrate in a co-culture with genistein-producing Streptomyces. Overall, our strategy of controlling microbial cell populations through physical constraints offers a promising approach for engineering synthetic microbial consortia for biotransformation at an industrial scale.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"24 1","pages":"48"},"PeriodicalIF":4.3,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11852520/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143492886","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":"Rap1 overexpression boosts triterpenoid saponin production in yeast by enhancing precursor supply and heterologous gene expression.","authors":"Ji-Young Byun, Thi Thuy Nguyen, Byung-Kwan Cho, Soo-Hoon Park, Sun-Chang Kim","doi":"10.1186/s12934-025-02667-3","DOIUrl":"10.1186/s12934-025-02667-3","url":null,"abstract":"<p><strong>Background: </strong>Metabolic engineering to increase the supply of precursors, such as 2,3-oxidosqualene (OSQ), and manipulate heterologous biosynthetic pathways through the strategic overexpression of multiple genes is promising for increasing the microbial production of triterpenoid saponins. However, the multiple use of constitutive promoters, typically derived from glycolytic or ribosomal protein promoters, can cause transcription factor competition, reducing the expression of each gene. To avoid this issue, we overexpressed transcriptional factor repressor activator protein 1 (Rap1), known to upregulate glycolytic gene expression and be involved in various metabolic pathways, including pyruvate dehydrogenase (PDH) bypass, the mevalonate (MVA) pathway, and sterol synthesis.</p><p><strong>Results: </strong>Transcriptome analysis of a wild-type yeast strain revealed that Rap1 overexpression significantly upregulated several central carbon metabolism (CCM)-related genes for OSQ production, including glycolytic genes, particularly after the diauxic shift phase. To validate the effect on triterpenoid saponin production, we engineered a Saccharomyces cerevisiae strain capable of producing ginsenoside compound K (CK). Notably, compared with the control strain, the CK-producing strain with Rap1 overexpression showed upregulation of heterologous genes controlled by TDH3 promoter, and a continuous supply of precursors to the CK synthesis pathway, resulting in a 4.5-fold increase in CK production.</p><p><strong>Conclusion: </strong>These results highlight Rap1 overexpression as a robust strategy to increase triterpenoid production in yeast cell factories. Additionally, this approach provides a versatile framework for enhancing both precursor supply and heterologous gene expression.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"24 1","pages":"47"},"PeriodicalIF":4.3,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11849169/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143492464","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":"Non-targeted metabolomic profile of Leuconostoc mesenteroides-fermented milk reveals differentially expressed metabolites associated with electro-fermentation.","authors":"Tristan Yusho Huang, John Jackson Yang","doi":"10.1186/s12934-025-02673-5","DOIUrl":"10.1186/s12934-025-02673-5","url":null,"abstract":"<p><strong>Background: </strong>Leuconostoc mesenteroides (L. mesenteroides) has known as an electrogenic probiotic bacterium. However, metabolites related to electro-fermentation in ferments of L. mesenteroides are not unveiled.</p><p><strong>Result: </strong>Electrogenic L. mesenteroides fermentatively metabolized bovine milk to dense ferments with homogeneous particle-size distribution. A non-targeted metabolomics approach was performed on non-fermented and L. mesenteroides-fermented milk. A total of 917 metabolites were identified and quantified by ultra-high performance liquid chromatography (UHPLC)-tandem mass spectrometry (MS-MS). Thirteen prokaryotic metabolic pathways associated with differentially expressed metabolites (DEMs) were revealed through Koto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. Anthranilic acid (AA) and 3-hydroxyanthranilin acid (3-HAA), potentially as electron donors, and quinolinic acid, an electron donor precursor, in the tryptophan kynurenine pathway were significantly increased in the fermented milk. Histidine, arginine, and riboflavin involved in bacterial survival or bioelectricity production were elevated after fermentation.</p><p><strong>Conclusions: </strong>Results indicate that electrogenic L. mesenteroides can mediate electro-fermentation to transform milk to a new nutritional source which is rich in electron donors reportedly acting as antioxidants.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"24 1","pages":"46"},"PeriodicalIF":4.3,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11847352/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143476702","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 potential application of isoxanthohumol in inhibiting Clostridium perfringens infection by targeting the type IV pili.","authors":"Zeyu Song, Yanhong Deng, Jichuan Zhang, Zhongmei Wen, Shui Liu, Xuming Deng, Qiaoling Zhang, Qianghua Lv","doi":"10.1186/s12934-025-02644-w","DOIUrl":"10.1186/s12934-025-02644-w","url":null,"abstract":"<p><strong>Background: </strong>Clostridium perfringens (C. perfringens) is an important zoonotic pathogen. The diseases such as necrotic enteritis (NE), enterotoxemia, gas gangrene and food poisoning caused by its infection seriously threaten the lives of both humans and animals. However, under the severe situation of antibiotic resistance, the development of new antibacterial strategies or drugs deserves great attention.</p><p><strong>Results: </strong>In this study, we selected the virulence factor Type IV pili (TFP) of C. perfringens as the target for drug screening. The gliding motility, biofilm formation, cell adhesion and antibacterial activity of the natural compound isoxanthohumol (IXN) against C. perfringens were determined. Transmission electron microscopy (TEM), TFP gene transcription analysis and Western blot were used to detect the expression of PilA pilin. The therapeutic effect of IXN on C. perfringens infection was demonstrated through a mouse gas gangrene model. It was confirmed that IXN inhibits the function of TFP by down-regulating TFP-encoding genes and two-component regulatory genes.</p><p><strong>Conclusions: </strong>In conclusion, our study shows that IXN has the potential to inhibit the function of TFP in C. perfringens and for anti-infection applications.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"24 1","pages":"45"},"PeriodicalIF":4.3,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11844124/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143468284","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":"Endophytic Aspergillus japonicus mediated biosynthesises of magnesium oxide nanoparticles: sustainable dye removal and in silico molecular docking evaluation of their enhanced antibacterial activity.","authors":"Reyad M El-Sharkawy, Mohamed Khairy, Magdi E A Zaki, Al-Shaimaa M Al-Tabbakh","doi":"10.1186/s12934-025-02648-6","DOIUrl":"10.1186/s12934-025-02648-6","url":null,"abstract":"<p><p>Sustainable biosynthesis of metal oxide nanoparticles using an eco-friendly approach is a growing research area owing to their promising environmental and biomedical applications. This work aims to biosynthesize and characterize magnesium oxide nanoparticles (MgONPS@Aj) for possible application in dye biosorption and antibacterial activity. For the first time, MgONPS@Aj was successfully synthesized by harnessing exometabolites of Aspergillus japonicus. Various parameters were statistically optimized to maximize the production of MgONPS@Aj using Plackett Burman's design and central composite design. The analysis of variance (ANOVA) revealed that pH was the most significant variable, affecting the bioproduction process followed by biomass quantity and Mg²⁺ precursor concentration. The suggested model (quadratic) was greatly significant and acceptable due to the nonsignificant lack of fit (15.10), and P-value (0.001). The optimized nanoparticles were characterized using X-ray powder diffraction, Fourier-transform infrared (FTIR) spectroscopy, transmission electron microscope (TEM), and Scanning electron microscopy. A high biosorption capacity (204.08 mg/g) of reactive black 5 dye was achieved within 40 min using a 5 mg biosorbent dose (MgONPS@Aj), 100 mg/l initial dye concentration, and pH 6.0. The biosorption process followed a pseudo-second-order (R² of 0.9842) and Langmuir isotherm (R² of 0.9422) models with a dimensionless separation factor (R_L) of 8 × 10⁴, hinting favorable and effective biosorption of dye molecules. A biosorption capacity of 81.97 mg/g after five successive cycles hints that the nanomaterial is suitable for several time utilization. Biogenic MgONPS@Aj displayed dramatic concentration-dependent antibacterial activity with the largest inhibition zones for P. aeruginosa (24.1 ± 0.8 mm, MIC: 3.125 µg/ml), followed by E. coli (22.3 ± 0.7 mm, MIC 6.25), B. subtilis (14.7 ± 0.4 mm, MIC: 12.5 µg/ml) and S. aureus (19.2 ± 0.6 mm, MIC: 6.25 µg/ml). The antibacterial activity was further interpreted using molecular simulation analysis. The lowest binding affinity was determined between MgONPS@Aj and target bacterial proteins (chloramphenicol acetyltransferase E. coli, and S. aureus MurE). The ligand (MgONPS@Aj) can bind to the active site's residues (Tyr¹⁷² and SER²²⁴), indicating a possible antibacterial mechanism. This study recommends MgONPS@Aj as an eco-friendly, and reusable alternative to traditional anionic dye sorbents and a uniquely promising candidate for antimicrobial applications.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"24 1","pages":"44"},"PeriodicalIF":4.3,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11843758/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143468279","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":"A novel recombinant PHB production platform in filamentous cyanobacteria avoiding nitrogen starvation while preserving cell viability.","authors":"Phillipp Fink, Claudia Menzel, Jong-Hee Kwon, Karl Forchhammer","doi":"10.1186/s12934-025-02650-y","DOIUrl":"10.1186/s12934-025-02650-y","url":null,"abstract":"<p><p>During the past decades, the importance of developing sustainable, carbon dioxide (CO₂)-neutral and biodegradable alternatives to conventional plastic has become evident in the context of global pollution issues. Therefore, heterotrophic bacteria such as Cupriavidus sp. have been intensively explored for the synthesis of the biodegradable polymer polyhydroxybutyrate (PHB). PHB is also naturally produced by a variety of phototrophic cyanobacteria, which only need sunlight and CO_2, thereby allowing a CO₂ negative, eco-friendly synthesis of this polymer. However, a major drawback of the use of cyanobacteria is the need of a two-stage production process, since relevant amount of PHB synthesis only occurs after transferring the cultures to conditions of nitrogen starvation, which hinders continuous, large-scale production.This study aimed at generating, by means of genetic engineering, a cyanobacterium that continuously produces PHB in large amounts. We choose a genetically amenable filamentous cyanobacterium of the genus Nostoc sp., which is a diazotrophic cyanobacterium, capable of atmospheric nitrogen (N₂) fixation but naturally does not produce PHB. We transformed this Nostoc strain with various constructs containing the constitutive promotor P_psbA and the PHB synthesis operon phaC1AB from Cupriavidus necator H16. In fact, while the transformants initially produced PHB, the PHB-producing strains rapidly lost cell viability. Therefore, we next attempted further optimization of the biosynthetic gene cluster. The PHB operon was expanded with phasin gene phaP1 from Cupriavidus necator H16 in combination with the native intergenic region of apcBA from Nostoc sp. 7120. Finally, we succeeded in stabilized PHB production, whilst simultaneously avoiding decreasing cell viability. In conclusion, the recombinant Nostoc strain constructed in the present work constitutes the first example of a continuous and stable PHB production platform in cyanobacteria, which has been decoupled from nitrogen starvation and, hence, harbours great potential for sustainable, industrial PHB production.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"24 1","pages":"43"},"PeriodicalIF":4.3,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11844001/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143468347","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}