Microbial Cell Factories最新文献

{"title":"Functional expression of recombinant insulins in Saccharomyces cerevisiae.","authors":"Mi-Jin Kim, Se-Lin Park, Hyun-Jin Kim, Bong Hyun Sung, Jung-Hoon Sohn, Jung-Hoon Bae","doi":"10.1186/s12934-024-02571-2","DOIUrl":"10.1186/s12934-024-02571-2","url":null,"abstract":"<p><strong>Background: </strong>Since 1982, recombinant insulin has been used as a substitute for pancreatic insulin from animals. However, increasing demand in medical and food industries warrants the development of more efficient production methods. In this study, we aimed to develop a novel and efficient method for insulin production using a yeast secretion system.</p><p><strong>Methods: </strong>Here, insulin C-peptide was replaced with a hydrophilic fusion partner (HL18) containing an affinity tag for the hypersecretion and easy purification of proinsulin. The HL18 fusion partner was then removed by in vitro processing with the Kex2 endoprotease (Kex2p), and authentic insulin was recovered via affinity chromatography. To improve the insulin functions, molecular chaperones of the host strain were reinforced via the constitutive expression of HAC1.</p><p><strong>Results: </strong>The developed method was successfully applied for the expression of cow, pig, and chicken insulins in yeast. Moreover, biological activity of recombinant insulins was confirmed by growth stimulation of cell line.</p><p><strong>Conclusions: </strong>Therefore, replacement of the C-peptide of insulin with the HL18 fusion partner and use of Kex2p for in vitro processing of proinsulin guarantees the economic production of animal insulins in yeast.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"23 1","pages":"302"},"PeriodicalIF":4.3,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11552327/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142623877","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 of a starch-fermenting Zymomonas mobilis strain for bioethanol production.","authors":"Yingchi Wei, Jia Li, Changhui Wang, Jiangke Yang, Wei Shen","doi":"10.1186/s12934-024-02539-2","DOIUrl":"10.1186/s12934-024-02539-2","url":null,"abstract":"<p><strong>Background: </strong>Biorefinery using microorganisms to produce biofuels and value-added biochemicals derived from renewable biomass offers a promising alternative to meet our sustainable energy and environmental goals. The ethanologenic strain Zymomonas mobilis is considered as an excellent chassis for constructing microbial cell factories for diverse biochemicals due to its outstanding industrial characteristics in ethanol production, high specific productivity, and Generally Recognized as Safe (GRAS) status. Nonetheless, the restricted substrate range constrains its application.</p><p><strong>Results: </strong>The truncated ice nucleation protein InaK from Pseudomonas syringae was used as an autotransporter passenger, and α-amylase was fused to the C- terminal of InaK to equip the ethanol-producing bacterium with the capability to ferment renewable biomass. Western blot and flow cytometry analysis confirmed that the amylase was situated on the outer membrane. Whole-cell activity assays demonstrated that the amylase maintained its activity on the cell surface. The recombinant Z. mobilis facilitated the hydrolysis of starch into oligosaccharides and enabled the streamlining of simultaneous saccharification and fermentation (SSF) processes. In a 5% starch medium under SSF, recombinant strains containing P_eno reached a maximum titer of 13.61 ± 0.12 g/L within 48 h. This represents an increase of 111.0% compared to the control strain's titer of titer of 6.45 ± 0.25 g/L.</p><p><strong>Conclusions: </strong>By fusing the truncated ice nucleation protein InaK with α-amylase, we achieved efficient expression and surface display of the enzyme on Z. mobilis. This fusion protein exhibited remarkable enzymatic activity. Its presence enabled a cost-effective bioproduction process using starch as the sole carbon source, and it significantly reduced the required cycle time for SSF. This study not only provides an excellent Z. mobilis chassis for sustainable bioproduction from starch but also highlights the potential of Z. mobilis to function as an effective cellular factory for producing high-value products from renewable biomass.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"23 1","pages":"301"},"PeriodicalIF":4.3,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11552318/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142623874","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":"Acetate production from corn stover hydrolysate using recombinant Escherichia coli BL21 (DE3) with an EP-bifido pathway.","authors":"Jieni Zhu, Wei Liu, Leilei Guo, Xiaoxu Tan, Weikang Sun, Hongxu Zhang, Hui Zhang, Wenjia Tian, Tianyi Jiang, Wensi Meng, Yidong Liu, Zhaoqi Kang, Chao Gao, Chuanjuan Lü, Ping Xu, Cuiqing Ma","doi":"10.1186/s12934-024-02575-y","DOIUrl":"10.1186/s12934-024-02575-y","url":null,"abstract":"<p><strong>Background: </strong>Acetate is an important chemical feedstock widely applied in the food, chemical and textile industries. It is now mainly produced from petrochemical materials through chemical processes. Conversion of lignocellulose biomass to acetate by biotechnological pathways is both environmentally beneficial and cost-effective. However, acetate production from carbohydrate in lignocellulose hydrolysate via glycolytic pathways involving pyruvate decarboxylation often suffers from the carbon loss and results in low acetate yield.</p><p><strong>Results: </strong>Escherichia coli BL21 (DE3) was confirmed to have high tolerance to acetate in this work. Thus, it was selected from seven laboratory E. coli strains for acetate production from lignocellulose hydrolysate. The byproduct-producing genes frdA, ldhA, and adhE in E. coli BL21 (DE3) were firstly knocked out to decrease the generation of succinate, lactate, and ethanol. Then, the genes pfkA and edd were also deleted and bifunctional phosphoketolase and fructose-1,6-bisphosphatase were overexpressed to construct an EP-bifido pathway in E. coli BL21 (DE3) to increase the generation of acetate from glucose. The obtained strain E. coli 5K/pFF can produce 22.89 g/L acetate from 37.5 g/L glucose with a yield of 0.61 g/g glucose. Finally, the ptsG gene in E. coli 5K/pFF was also deleted to make the engineered strain E. coli 6K/pFF to simultaneously utilize glucose and xylose in lignocellulosic hydrolysates. E. coli 6K/pFF can produce 20.09 g/L acetate from corn stover hydrolysate with a yield of 0.52 g/g sugar.</p><p><strong>Conclusion: </strong>The results presented here provide a promising alternative for acetate production with low cost substrate. Besides acetate production, other biotechnological processes might also be developed for other acetyl-CoA derivatives production with lignocellulose hydrolysate through further metabolic engineering of E. coli 6K/pFF.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"23 1","pages":"300"},"PeriodicalIF":4.3,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11552437/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142623872","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":"Towards maximizing biomass and lipid productivity: high-throughput screening assay for prospecting heterotrophic growth for new microalgal isolates.","authors":"Su-Bin Park, Yu Rim Lee, Jin-Ho Yun, Hong Il Choi, Eun Jeong Sim, Dong-Yun Choi, Dae-Hyun Cho, Hee-Sik Kim, Yong Jae Lee","doi":"10.1186/s12934-024-02550-7","DOIUrl":"10.1186/s12934-024-02550-7","url":null,"abstract":"<p><strong>Background: </strong>Microalgae have emerged as sustainable alternatives to fossil fuels and high-value petrochemicals. Despite the commercial potential of microalgae, their low biomass productivity is a significant limiting factor for large-scale production. In the photoautotrophic cultivation of microalgae, achievable cell density levels depend on the light transmittance of the production system, which can significantly decrease the photosynthetic rate and biomass production. In contrast, the mixotrophic cultivation of microalgae using heterotrophic carbon sources enables high-density cultivation, which significantly enhances biomass productivity. The identification of optimal production conditions is crucial for improving biomass productivity; however, it is typically time- and resource-consuming. To overcome this problem, high-throughput screening (HTS) system presents a practical approach to maximize biomass and lipid production and enhance the industrial applicability of microalgae.</p><p><strong>Results: </strong>In this study, we proposed a two-step HTS assay that allows effective screening of heterotrophic conditions compatible with new microalgal isolates. To confirm the effectiveness of the HTS assay, three microalgal isolates with distinctive morphological and genetic traits were selected. Suitable cultivation conditions, including various heterotrophic carbon sources, substrate concentrations, and temperatures, were investigated using a two-step HTS assay. The optimized conditions were validated at the flask scale, which confirmed a significant enhancement in the biomass and lipid productivity of each isolate. Moreover, the two-step HTS assay notably enhanced economic and temporal efficiency compared to conventional flask-based optimization.</p><p><strong>Conclusions: </strong>These results suggest that our two-step HTS assay is an efficient strategy for investigating and optimizing microalgal culture conditions to maximize biomass and lipid productivity. This approach has the potential to enhance the industrial applicability of microalgae and facilitate the seamless transition from laboratory to field applications.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"23 1","pages":"299"},"PeriodicalIF":5.4,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11545793/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142604123","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":"Screening of novel β-carotene hydroxylases for the production of β-cryptoxanthin and zeaxanthin and the impact of enzyme localization and crowding on their production in Yarrowia lipolytica.","authors":"Mladen Soldat, Tadej Markuš, Vasilka Magdevska, Martin Kavšček, Aleksander Johannes Kruis, Jaka Horvat, Gregor Kosec, Štefan Fujs, Uroš Petrovič","doi":"10.1186/s12934-024-02569-w","DOIUrl":"10.1186/s12934-024-02569-w","url":null,"abstract":"<p><p>Zeaxanthin, a vital dietary carotenoid, is naturally synthesized by plants, microalgae, and certain microorganisms. Large-scale zeaxanthin production can be achieved through plant extraction, chemical synthesis, or microbial fermentation. The environmental and health implications of the first two methods have made microbial fermentation an appealing alternative for natural zeaxanthin production despite the challenges in scaling up the bioprocess. An intermediate between β-carotene and zeaxanthin, β-cryptoxanthin, is found only in specific fruits and vegetables and has several important functions for human health. The low concentration of β-cryptoxanthin in these sources results in low extraction yields, making biotechnological production a promising alternative for achieving higher yields. Currently, there is no industrially relevant microbial fermentation process for β-cryptoxanthin production, primarily due to the lack of identified enzymes that specifically convert β-carotene to β-cryptoxanthin without further conversion to zeaxanthin. In this study, we used genetic engineering to leverage the oleaginous yeast Yarrowia lipolytica as a bio-factory for zeaxanthin and β-cryptoxanthin production. We screened 22 β-carotene hydroxylases and identified eight novel enzymes with β-carotene hydroxylating activity: six producing zeaxanthin and two producing only β-cryptoxanthin. By introducing the β-carotene hydroxylase from the bacterium Chondromyces crocatus (CcBCH), a β-cryptoxanthin titer of 24 ± 6 mg/L was achieved, representing the highest reported titer of sole β-cryptoxanthin in Y. lipolytica to date. By targeting zeaxanthin-producing β-carotene hydroxylase to the endoplasmic reticulum and peroxisomes, we increased the production of zeaxanthin by 54% and 66%, respectively, compared to untargeted enzyme. The highest zeaxanthin titer of 412 ± 34 mg/L was achieved by targeting β-carotene hydroxylases to peroxisomes. In addition, by constructing multienzyme scaffold-free complexes with short peptide tags RIDD and RIAD, we observed a 39% increase in the zeaxanthin titer and a 28% increase in the conversion rate compared to the strain expressing unmodified enzyme. The zeaxanthin titers obtained in this study are not the highest reported; however, our goal was to demonstrate that specific approaches can enhance both titer and conversion rate, rather than to achieve the maximum titer. These findings underscore the potential of Y. lipolytica as a promising platform for carotenoid production and provide a foundation for future research, where further optimization is required to maximize production.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"23 1","pages":"298"},"PeriodicalIF":4.3,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11536915/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142583710","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":"Understanding energy fluctuation during the transition state: The role of AbrB in Bacillus licheniformis.","authors":"Qing Zhang, Wanying Zhu, Shisi He, Jiaqi Lei, Liangsheng Xu, Shiying Hu, Zheng Zhang, Dongbo Cai, Shouwen Chen","doi":"10.1186/s12934-024-02572-1","DOIUrl":"10.1186/s12934-024-02572-1","url":null,"abstract":"<p><strong>Background: </strong>Limited research has been conducted on energy fluctuation during the transition state, despite the critical role of energy supply in microbial physiological metabolism.</p><p><strong>Results: </strong>This study aimed to investigate the regulatory function of transition state transcription factor AbrB on energy metabolism in Bacillus licheniformis WX-02. Firstly, the deletion of abrB was found to prolong the cell generation time, significantly reducing the intercellular ATP concentration and NADH/NAD⁺ ratio at the early stage. Subsequently, various target genes and transcription factors regulated by AbrB were identified through in vitro verification assays. Specifically, AbrB was shown to modulate energy metabolism by directly regulating the expression of genes pyk and pgk in substrate-level phosphorylation, as well as genes narK and narGHIJ associated with nitrate respiration. In terms of oxidative phosphorylation, AbrB not only directly regulated ATP generation genes, including cyd, atpB, hmp, ndh, qoxA and sdhC, but also influenced the expression of NAD-dependent enzymes and intracellular NADH/NAD⁺ ratio. Additionally, AbrB positively affected the expression of transcription factors CcpN, Fnr, Rex, and ResD involved in energy supply, while negatively affected the regulator CcpA. Overall, this study found that AbrB positively regulates both substrate-level phosphorylation and oxidative phosphorylation, while negatively regulating nitrate respiration.</p><p><strong>Conclusions: </strong>This study proposes a comprehensive regulatory network of AbrB on energy metabolism in Bacillus, expanding the understanding of regulatory mechanisms of AbrB and elucidating energy fluctuations during the transition state.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"23 1","pages":"296"},"PeriodicalIF":4.3,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11533420/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142569066","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":"Improvement of succinate production from methane by combining rational engineering and laboratory evolution in Methylomonas sp. DH-1.","authors":"Jae-Hwan Jo, Jeong-Ho Park, Byung Kwon Kim, Seon Jeong Kim, Chan Mi Park, Chang Keun Kang, Yong Jun Choi, Hyejin Kim, Eun Yeol Lee, Myounghoon Moon, Gwon Woo Park, Sangmin Lee, Soo Youn Lee, Jin-Suk Lee, Won-Heong Lee, Jeong-Il Kim, Min-Sik Kim","doi":"10.1186/s12934-024-02557-0","DOIUrl":"10.1186/s12934-024-02557-0","url":null,"abstract":"<p><p>Recently, methane has been considered a next-generation carbon feedstock due to its abundance and it is main component of shale gas and biogas. Methylomonas sp. DH-1 has been evaluated as a promising industrial bio-catalyst candidate. Succinate is considered one of the top building block chemicals in the agricultural, food, and pharmaceutical industries. In this study, succinate production by Methylomonas sp. DH-1 was improved by combining adaptive laboratory evolution (ALE) technology with genetic engineering in the chromosome of Methylomonas sp. DH-1, such as deletion of bypass pathway genes (succinate dehydrogenase and succinate semialdehyde dehydrogenase) or overexpression of genes related with succinate production (citrate synthase, pyruvate carboxylase and phosphoenolpyruvate carboxylase). Through ALE, the maximum consumption rate of substrate gases (methane and oxygen) and the duration maintaining high substrate gas consumption rates was enhanced compared to those of the parental strain. Based on the improved methane consumption, cell growth (OD₆₀₀) increased more than twice, and the succinate titer increased by ~ 48% from 218 to 323 mg/L. To prevent unwanted succinate consumption, the succinate semialdehyde dehydrogenase gene was deleted from the genome. The first enzyme of TCA cycle (citrate synthase) was overexpressed. Pyruvate carboxylase and phosphoenolpyruvate carboxylase, which produce oxaloacetate, a substrate for citrate synthase, were also overproduced by a newly identified strong promoter. The new strong promoter was screened from RNA sequencing data. When these modifications were combined in one strain, the maximum titer (702 mg/L) was successfully improved by more than three times. This study demonstrates that successful enhancement of succinic acid production can be achieved in methanotrophs through additional genetic engineering following adaptive laboratory evolution.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"23 1","pages":"297"},"PeriodicalIF":4.3,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11533326/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142576551","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":"13 C-MFA helps to identify metabolic bottlenecks for improving malic acid production in Myceliophthora thermophila.","authors":"Junfeng Jiang, Defei Liu, Jingen Li, Chaoguang Tian, Yingping Zhuang, Jianye Xia","doi":"10.1186/s12934-024-02570-3","DOIUrl":"10.1186/s12934-024-02570-3","url":null,"abstract":"<p><strong>Background: </strong>Myceliophthora thermophila has been engineered as a significant cell factory for malic acid production, yet strategies to further enhance production remain unclear and lack rational guidance. ¹³C-MFA (¹³C metabolic flux analysis) offers a means to analyze cellular metabolic mechanisms and pinpoint critical nodes for improving product synthesis. Here, we employed ¹³C-MFA to investigate the metabolic flux distribution of a high-malic acid-producing strain of M. thermophila and attempted to decipher the crucial bottlenecks in the metabolic pathways.</p><p><strong>Results: </strong>Compared with the wild-type strain, the high-Malic acid-producing strain M. thermophila JG207 exhibited greater glucose uptake and carbon dioxide evolution rates but lower oxygen uptake rates and biomass yields. Consistent with these phenotypes, the ¹³C-MFA results showed that JG207 displayed elevated flux through the EMP pathway and downstream TCA cycle, along with reduced oxidative phosphorylation flux, thereby providing more precursors and NADH for malic acid synthesis. Furthermore, based on the ¹³C-MFA results, we conducted oxygen-limited culture and nicotinamide nucleotide transhydrogenase (NNT) gene knockout experiments to increase the cytoplasmic NADH level, both of which were shown to be beneficial for malic acid accumulation.</p><p><strong>Conclusions: </strong>This work elucidates and validates the key node for achieving high malic acid production in M. thermophila. We propose effective fermentation strategies and genetic modifications for enhancing malic acid production. These findings offer valuable guidance for the rational design of future cell factories aimed at improving malic acid yields.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"23 1","pages":"295"},"PeriodicalIF":4.3,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11531171/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142564784","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":"Thermo-adaptive evolution of Corynebacterium glutamicum reveals the regulatory functions of fasR and hrcA in heat tolerance.","authors":"Weidong Li, Jian Yang, Yuxiang Chen, Ning Xu, Jun Liu, Jian Wang","doi":"10.1186/s12934-024-02568-x","DOIUrl":"10.1186/s12934-024-02568-x","url":null,"abstract":"<p><strong>Background: </strong>High-temperature fermentation technology is promising in improving fermentation speed and product quality, and thereby widely used in various fields such as food, pharmaceuticals, and biofuels. However, extreme temperature conditions can disrupt cell membrane structures and interfere with the functionality of biological macromolecules (e.g. proteins and RNA), exerting detrimental effects on cellular viability and fermentation capability.</p><p><strong>Results: </strong>Herein, a microbial thermotolerance improvement strategy was developed based on adaptive laboratory evolution (ALE) for efficient high-temperature fermentation. Employing this strategy, we have successfully obtained Corynebacterium glutamicum strains with superior resistance to high temperatures. Specifically, the genome analysis indicated that the evolved strains harbored 13 missense genetic mutations and 3 same-sense genetic mutations compared to the non-evolved parent strain. Besides, reverse transcription quantitative PCR analysis (RT qPCR) of the hrcA-L119P mutant demonstrated that both groEL genes were upregulated under 42 °C, which enabled the construction of robust strains with improved heat tolerance. Furthermore, a significant increase in FAS-IA and FAS-IB expression of the fasR-L102F strain was proved to play a key role in protecting cells against heat stress.</p><p><strong>Conclusions: </strong>This work systematically reveals the thermotolerance mechanisms of Corynebacterium glutamicum and opens a new avenue for revolutionizing the design of cell factories to boost fermentation efficiency.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"23 1","pages":"294"},"PeriodicalIF":4.3,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11520817/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142522402","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":"Engineering of bacteria towards programmed autolysis: why, how, and when?","authors":"Changying Dong, Shenghao Cui, Jialuan Ren, Guoli Gong, Jian Zha, Xia Wu","doi":"10.1186/s12934-024-02566-z","DOIUrl":"10.1186/s12934-024-02566-z","url":null,"abstract":"<p><p>Programmed autolytic bacteria, also termed controlled self-disruptive or self-destructive bacteria, are bacterial systems that express certain lytic genes and undergo cell lysis at a predetermined time point to release the intracellular contents or to commit suicide. Such systems have wide applications in high-throughput screening of protein libraries, synthesis and recovery of bio-products, population control of heterogeneous cultures or synthetic co-cultures, drug delivery, and food fermentation. Recently, great achievements have been reported regarding on-demand control of cell autolysis for different purposes, highlighting the potential of autolytic strains in biomanufacturing and biomedicine. In this review article, we first introduce the various applications of such bacteria, followed by a summarization of the approaches used in the establishment of autolytic bacterial systems, including cell autolysis mediated by cell wall hydrolases with or without facilitating proteins and by membrane-disturbing proteins. Next, we describe in detail the methodologies adopted to control and initiate cell lysis, including induction by chemical inducers, stimulation by physical signals, auto-induction by metabolic status or nutrient limitation, and constitutive expression of the lytic genes. This article is ended with discussions on the remaining problems and possible future directions. This review provides comprehensive information on autolytic bacteria and insightful guidance to the development of highly efficient, robust, and smart autolytic bacterial platforms.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"23 1","pages":"293"},"PeriodicalIF":4.3,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11514776/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142503946","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}