Metabolic engineering最新文献

{"title":"AI-based automated construction of high-precision Geobacillus thermoglucosidasius enzyme constraint model.","authors":"Minghao Zhang,Haijiao Shi,Xiaohong Wang,Yanan Zhu,Zilong Li,Linna Tu,Yu Zheng,Menglei Xia,Weishan Wang,Min Wang","doi":"10.1016/j.ymben.2024.10.006","DOIUrl":"https://doi.org/10.1016/j.ymben.2024.10.006","url":null,"abstract":"Geobacillus thermoglucosidasius NCIMB 11955 possesses advantages, such as high-temperature tolerance, rapid growth rate, and low contamination risk. Additionally, it features efficient gene editing tools, making it one of the most promising next-generation cell factories. However, as a non-model microorganism, a lack of metabolic information significantly hampers the construction of high-precision metabolic flux models. Here, we propose a BioIntelliModel (BIM) strategy based on artificial intelligence technology for the automated construction of enzyme-constrained models. 1) . BIM utilises the Contrastive Learning Enabled Enzyme Annotation (CLEAN) prediction tool to analyse the entire genome sequence of G. thermoglucosidasius NCIMB 11955, uncovering potential functional proteins in non-model strains. 2). The MetaPatchM module of BIM automates the repair of the metabolic network model. 3). The Tianjin University of Science and Technology-kcat (TUST-kcat) module predicts the kcat values of enzymes within the model. 4). The Enzyme-insert procedure constructs an enzyme-constrained model and performs a global scan to address overconstraint issues. Enzymatic data were automatically integrated into the metabolic flux model, creating an enzyme-constrained model, ec_G-ther11955. To validate model accuracy, we used both the p-thermo and ec_G-ther11955 models to predict riboflavin production strategies. The ec_G-ther11955 model demonstrated significantly higher accuracy. To further verify its efficacy, we employed ec_G-ther11955 to guide the rational design of L-valine-producing strains. Using the Optimisation Procedure for Identifying All Genetic Manipulations Leading to Targeted Overproductions (OptForce), Predictive Knockout Targeting (PKT), and Flux Scanning based on Enforced Objective Flux (FSEOF) algorithms, we identified 24 knockout and overexpression targets, achieving an accuracy rate of 87.5%. Ultimately, this led to an increase of 664.04% in L-valine titre. This study provides a novel strategy for rapidly constructing non-model strain models and demonstrates the tremendous potential of artificial intelligence in metabolic engineering.","PeriodicalId":18483,"journal":{"name":"Metabolic engineering","volume":"33 1","pages":""},"PeriodicalIF":8.4,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142486335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"AI-based automated construction of high-precision Geobacillus thermoglucosidasius enzyme constraint model","authors":"Minghao Zhang ,&nbsp;Haijiao Shi ,&nbsp;Xiaohong Wang ,&nbsp;Yanan Zhu ,&nbsp;Zilong Li ,&nbsp;Linna Tu ,&nbsp;Yu Zheng ,&nbsp;Menglei Xia ,&nbsp;Weishan Wang ,&nbsp;Min Wang","doi":"10.1016/j.ymben.2024.10.006","DOIUrl":"10.1016/j.ymben.2024.10.006","url":null,"abstract":"<div><div><em>Geobacillus thermoglucosidasius</em> NCIMB 11955 possesses advantages, such as high-temperature tolerance, rapid growth rate, and low contamination risk. Additionally, it features efficient gene editing tools, making it one of the most promising next-generation cell factories. However, as a non-model microorganism, a lack of metabolic information significantly hampers the construction of high-precision metabolic flux models. Here, we propose a BioIntelliModel (BIM) strategy based on artificial intelligence technology for the automated construction of enzyme-constrained models. 1). BIM utilises the Contrastive Learning Enabled Enzyme Annotation (CLEAN) prediction tool to analyse the entire genome sequence of <em>G. thermoglucosidasius</em> NCIMB 11955, uncovering potential functional proteins in non-model strains. 2). The MetaPatchM module of BIM automates the repair of the metabolic network model. 3). The Tianjin University of Science and Technology-<em>k</em>_cat (TUST-<em>k</em>_cat) module predicts the <em>k</em>_cat values of enzymes within the model. 4). The Enzyme-insert procedure constructs an enzyme-constrained model and performs a global scan to address overconstraint issues. Enzymatic data were automatically integrated into the metabolic flux model, creating an enzyme-constrained model, ec_G-ther11955. To validate model accuracy, we used both the <em>p-thermo</em> and ec_G-ther11955 models to predict riboflavin production strategies. The ec_G-ther11955 model demonstrated significantly higher accuracy. To further verify its efficacy, we employed ec_G-ther11955 to guide the rational design of L-valine-producing strains. Using the Optimisation Procedure for Identifying All Genetic Manipulations Leading to Targeted Overproductions (OptForce), Predictive Knockout Targeting (PKT), and Flux Scanning based on Enforced Objective Flux (FSEOF) algorithms, we identified 24 knockout and overexpression targets, achieving an accuracy rate of 87.5%. Ultimately, this led to an increase of 664.04% in L-valine titre. This study provides a novel strategy for rapidly constructing non-model strain models and demonstrates the tremendous potential of artificial intelligence in metabolic engineering.</div></div>","PeriodicalId":18483,"journal":{"name":"Metabolic engineering","volume":"86 ","pages":"Pages 208-233"},"PeriodicalIF":6.8,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142469629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Butyrate as a growth factor of Clostridium acetobutylicum","authors":"Hyeongmin Seo,&nbsp;Sofia H. Capece,&nbsp;John D. Hill,&nbsp;Jonathan K. Otten,&nbsp;Eleftherios T. Papoutsakis","doi":"10.1016/j.ymben.2024.10.005","DOIUrl":"10.1016/j.ymben.2024.10.005","url":null,"abstract":"<div><div>The butyrate biosynthetic pathway not only contributes to electron management and energy generation in butyrate forming bacteria, but also confers evolutionary advantages to the host by inhibiting the growth of surrounding butyrate-sensitive microbes. While high butyrate levels induce toxic stress, effects of non-toxic levels on cell growth, health, metabolism, and sporulation remain unclear. Here, we show that butyrate stimulates cellular processes of <em>Clostridium acetobutylicum</em>, a model butyrate forming Firmicute. First, we deleted the 3-hydroxybutyryl-CoA dehydrogenase gene (<em>hbd</em>) from the <em>C. acetobutylicum</em> chromosome to eliminate the butyrate synthetic pathway and thus butyrate formation. A xylose inducible Cas9 cassette was chromosomally integrated and utilized for the one-step markerless gene deletions. Non-toxic butyrate levels significantly affected growth, health, and sporulation of <em>C. acetobutylicum</em>. After deleting <em>spo0A</em>, the gene encoding the master regulator of sporulation, Spo0A, and conducting butyrate addition experiments, we conclude that butyrate affects cellular metabolism through both Spo0A-dependent and independent mechanisms. We also deleted the <em>hbd</em> gene from the chromosome of the asporogenous <em>C. acetobutylicum</em> M5 strain lacking the pSOL1 plasmid to examine the potential involvement of pSOL1 genes on the observed butyrate effects. Addition of crotonate, the precursor of butyrate biosynthesis, to the <em>hbd</em> deficient M5 strain was used to probe the role of butyrate biosynthesis pathway in electron and metabolic fluxes. Finally, we found that butyrate addition can enhance the growth of the non-butyrate forming <em>Clostridium saccharolyticum</em>. Our data suggest that butyrate functions as a stimulator of cellular processes, like a growth factor, in <em>C. acetobutylicum</em> and potentially evolutionarily related <em>Clostridium</em> organisms.</div></div>","PeriodicalId":18483,"journal":{"name":"Metabolic engineering","volume":"86 ","pages":"Pages 194-207"},"PeriodicalIF":6.8,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142469630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Growth-coupled production of L-isoleucine in Escherichia coli via metabolic engineering","authors":"Nan Lu ,&nbsp;Minhua Wei ,&nbsp;Xuejing Yang ,&nbsp;Yingzi Li ,&nbsp;Hao Sun ,&nbsp;Qianyu Yan ,&nbsp;Haibin Zhang ,&nbsp;Jilong He ,&nbsp;Jie Ma ,&nbsp;Menglei Xia ,&nbsp;Chenglin Zhang","doi":"10.1016/j.ymben.2024.10.004","DOIUrl":"10.1016/j.ymben.2024.10.004","url":null,"abstract":"<div><div>L-isoleucine, an essential amino acid, is widely used in the pharmaceutical and food industries. However, the current production efficiency is insufficient to meet the increasing demands. In this study, we aimed to develop an efficient L-isoleucine-producing strain of <em>Escherichia coli</em>. First, accumulation of L-isoleucine was achieved by employing feedback-resistant enzymes. Next, a growth-coupled L-isoleucine synthetic pathway was established by introducing the <em>metA</em>-<em>metB</em>-based α-ketobutyrate-generating bypass, which significantly increased L-isoleucine production to 7.4 g/L. Upon employing an activity-improved cystathionine γ-synthase mutant obtained from adaptive laboratory evolution, L-isoleucine production further increased to 8.5 g/L. Subsequently, the redox flux was improved by bypassing the NADPH-dependent aspartate aminotransferase pathway and employing the NADH-dependent pathway and transhydrogenase. Finally, L-isoleucine efflux was enhanced by modifying the transport system. After fed-batch fermentation for 48 h, the resultant strain, ISO-12, reached an L-isoleucine production titer of 51.5 g/L and yield of 0.29 g/g glucose. The strains developed in this study achieved a higher L-isoleucine production efficiency than those reported previously. These strategies will aid in the development of cell factories that produce L-isoleucine and related products.</div></div>","PeriodicalId":18483,"journal":{"name":"Metabolic engineering","volume":"86 ","pages":"Pages 181-193"},"PeriodicalIF":6.8,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142447953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improving the growth and intestinal colonization of Escherichia coli Nissle 1917 by strengthening its oligopeptides importation ability","authors":"Ruxue Sun ,&nbsp;Peijun Yu ,&nbsp;Liying Guo ,&nbsp;Yufei Huang ,&nbsp;Yanhong Nie ,&nbsp;Yunpeng Yang","doi":"10.1016/j.ymben.2024.10.002","DOIUrl":"10.1016/j.ymben.2024.10.002","url":null,"abstract":"<div><div><em>Escherichia coli</em> Nissle 1917 (EcN), the probiotic featured with well-established safety in different host, is emerging as a favored chassis for the construction of engineered probiotics for disease treatment. However, limited by the low intestinal colonization ability of EcN, repeated administration is required to maximize the health benefits of the EcN-derived engineered probiotics. Here, using fecal metabolites as “metabolites pool”, we developed a metabolomic strategy to characterize the comprehensive metabolic profile of EcN. Compared with <em>Prevotella copri</em> DSM 18205 (<em>P. copri</em>), one of the dominant microbes in gut flora, EcN exhibited minor growth advantage under the fecal metabolites-containing condition for its lower metabolic capability towards fecal metabolites. Further study indicated that EcN lacked the ability to import the oligopeptides containing more than two amino acids. The shortage of oligopeptides-derived amino acids might limit the growth of EcN by restricting its purine metabolism. Assisted with the bioinformatic and qRT-PCR analyses, we identified a tripeptides-specific importer Pc-OPT in <em>P. copri</em>, which was mainly distributed in genera <em>Prevotella</em> and <em>Bacteroides</em>. Overexpression of Pc-OPT improved the tripeptides importation of EcN and promoted its growth and intestinal colonization. Notably, 16S rRNA gene amplicon sequencing results indicated that strengthening the oligopeptides importation ability of EcN might promote its intestinal colonization by adjusting the gut microbial composition. Our study reveals that the growth and intestinal colonization of EcN is limited by its insufficient oligopeptides importation and paves road for promoting the efficacy of the EcN-derived synthetic probiotics by improving their intestinal colonization ability.</div></div>","PeriodicalId":18483,"journal":{"name":"Metabolic engineering","volume":"86 ","pages":"Pages 157-171"},"PeriodicalIF":6.8,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142400708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 a novel pathway for efficient biosynthesis of salicin in Escherichia coli","authors":"Jingyan Wang,&nbsp;Qianjing Zhao,&nbsp;Xin Chen,&nbsp;Yichen Lu,&nbsp;Xinxiao Sun,&nbsp;Qipeng Yuan,&nbsp;Jia Wang,&nbsp;Xiaolin Shen","doi":"10.1016/j.ymben.2024.10.003","DOIUrl":"10.1016/j.ymben.2024.10.003","url":null,"abstract":"<div><div>Salicin is a natural glycoside compound widely used to treat fever, inflammation, and analgesia. Currently, salicin is primarily extracted from willow bark, which is not only cumbersome in terms of extraction and separate steps, but also subject to seasonal and geographic limitations. In this study, a highly efficient biosynthetic pathway for salicin synthesis was designed and constructed in <em>E. coli</em>. The most important precursor in the synthetic pathway of salicin designed in this study is salicyl alcohol. Building on a previously constructed biosynthetic salicylic acid metabolic pathway, the production of salicyl alcohol in shake flask fermentation reached 1.7 g/L by increasing the supply of shikimic acid pathway precursor PEP and salicyl alcohol precursor chorismate. According to the principle of substrate similarity, this study identified the key enzyme OsSGT1 from <em>Oryza sativa</em>, which uses <em>E. coli</em> endogenous UDP-glucose as a glycosyl donor to glycosylate salicyl alcohol into salicin. By redefining the optimal substrate of OsSGT1, and balancing metabolic flux along with increasing the supply of UDP-glucose, salicin production in shake flasks reached 4 g/L. Finally, culturing the high-yield strain in a 3-L fermenter resulted in the synthesis of 14.62 g/L of salicin. To the best of our knowledge, this achievement marks the highest salicin production through microbial fermentation to date.</div></div>","PeriodicalId":18483,"journal":{"name":"Metabolic engineering","volume":"86 ","pages":"Pages 172-180"},"PeriodicalIF":6.8,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142400707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hyperproduction of 7-dehydrocholesterol by rewiring the post-squalene module in lipid droplets of Saccharomyces cerevisiae","authors":"Xiang Xiu ,&nbsp;Xianhao Xu ,&nbsp;Yaokang Wu ,&nbsp;Yanfeng Liu ,&nbsp;Jianghua Li ,&nbsp;Guocheng Du ,&nbsp;Jian Chen ,&nbsp;Xueqin Lv ,&nbsp;Long Liu","doi":"10.1016/j.ymben.2024.10.001","DOIUrl":"10.1016/j.ymben.2024.10.001","url":null,"abstract":"<div><div>Lipid droplets (LDs) are specialized organelles that store neutral lipids to reduce the negative effects of lipotoxicity on cells. However, many neutral lipids are precursors for the synthesis of sterols and complex terpenoids, and this sequestration often greatly limits the efficient biosynthesis of sterols and complex terpenoids. In this study, taking 7-dehydrocholesterol (7-DHC) synthesis in <em>Saccharomyces cerevisiae</em> as an example, we revealed the blocking mechanism of LD sequestration on the efficient synthesis of metabolic products and found that LDs can sequester a significant amount of squalene, the precursor of 7-DHC, effectively preventing it from being directed toward the post-squalene pathway. Based on this, a post-squalene pathway was reconstructed on LDs, which resulted in a 28.7% increase in the 7-DHC titer, reaching 684.1 mg/L, whereas the squalene titer was reduced by approximately 97%. Subsequently, the triacylglycerol degradation pathway was weakened to release the storage space in LDs, and the esterification pathway was concurrently strengthened to guide 7-DHC storage within LDs, which further increased 7-DHC production, reaching 792.9 mg/L. Finally, by reducing the NADH/NAD + ratio to alleviate the redox imbalance, the 7-DHC titer reached 867.6 mg/L in shake flask and 5.1 g/L in a 3-L bioreactor, which is the highest reported titer to date. In summary, this study provides new insights into the important role of LDs in sterol synthesis and offers a novel strategy for constructing cell factories for the efficient synthesis of sterol compounds.</div></div>","PeriodicalId":18483,"journal":{"name":"Metabolic engineering","volume":"86 ","pages":"Pages 147-156"},"PeriodicalIF":6.8,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142385364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Metabolic engineering of yeast for de novo production of kratom monoterpene indole alkaloids","authors":"Maxence Holtz ,&nbsp;Daniela Rago ,&nbsp;Ida Nedermark ,&nbsp;Frederik G. Hansson ,&nbsp;Beata J. Lehka ,&nbsp;Lea G. Hansen ,&nbsp;Nils E.J. Marcussen ,&nbsp;Wouter J. Veneman ,&nbsp;Linda Ahonen ,&nbsp;Juraithip Wungsintaweekul ,&nbsp;Carlos G. Acevedo-Rocha ,&nbsp;Ron P. Dirks ,&nbsp;Jie Zhang ,&nbsp;Jay D. Keasling ,&nbsp;Michael K. Jensen","doi":"10.1016/j.ymben.2024.09.011","DOIUrl":"10.1016/j.ymben.2024.09.011","url":null,"abstract":"<div><div>Monoterpene indole alkaloids (MIAs) from <em>Mitragyna speciosa</em> (“kratom”), such as mitragynine and speciogynine, are promising novel scaffolds for opioid receptor ligands for treatment of pain, addiction, and depression. While kratom leaves have been used for centuries in South-East Asia as stimulant and pain management substance, the biosynthetic pathway of these psychoactives have only recently been partially elucidated. Here, we demonstrate the <em>de novo</em> production of mitragynine and speciogynine in <em>Saccharomyces cerevisiae</em> through the reconstruction of a five-step synthetic pathway from common MIA precursor strictosidine comprising fungal tryptamine 4-monooxygenase to bypass an unknown kratom hydroxylase. Upon optimizing cultivation conditions, a titer of ∼290 μg/L kratom MIAs from glucose was achieved. Untargeted metabolomics analysis of lead production strains led to the identification of numerous shunt products derived from the activity of strictosidine synthase (STR) and dihydrocorynantheine synthase (DCS), highlighting them as candidates for enzyme engineering to further improve kratom MIAs production in yeast. Finally, by feeding fluorinated tryptamine and expressing a human tailoring enzyme, we further demonstrate production of fluorinated and hydroxylated mitragynine derivatives with potential applications in drug discovery campaigns. Altogether, this study introduces a yeast cell factory platform for the biomanufacturing of complex natural and new-to-nature kratom MIAs derivatives with therapeutic potential.</div></div>","PeriodicalId":18483,"journal":{"name":"Metabolic engineering","volume":"86 ","pages":"Pages 135-146"},"PeriodicalIF":6.8,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142375608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"α-Substituted 3-hydroxy acid production from glucose in Escherichia coli","authors":"K'yal R. Bannister,&nbsp;Kristala L.J. Prather","doi":"10.1016/j.ymben.2024.09.006","DOIUrl":"10.1016/j.ymben.2024.09.006","url":null,"abstract":"<div><div>Polyhydroxyalkanoates (PHAs) are renewably-derived, microbial polyesters composed of hydroxy acids (HAs). Demand for sustainable plastics alternatives, combined with the unfavorable thermal properties exhibited by some PHAs, motivates the discovery of novel PHA-based materials. Incorporation of α-substituted HAs yields thermostable PHAs; however, the reverse β-oxidation (rBOX) pathway, the canonical pathway for HA production, is unable to produce these monomers because it utilizes thiolases with narrow substrate specificity. Here, we present a thiolase-independent pathway to two α-substituted HAs, 3-hydroxyisobutyric acid (3HIB) and 3-hydroxy-2-methylbutyric acid (3H2MB). This pathway involves the conversion of glucose to various branched acyl-CoAs and ultimately to 3HIB or 3H2MB. As proof of concept, we engineered <em>Escherichia coli</em> for the specific production of 3HIB and 3H2MB from glucose at titers as high as 66 ± 5 mg/L and 290 ± 40 mg/L, respectively. Optimizing this pathway for 3H2MB production via a novel byproduct recycle increased titer by 60%. This work illustrates the utility of novel pathway design HA production leading to PHAs with industrially relevant properties.</div></div>","PeriodicalId":18483,"journal":{"name":"Metabolic engineering","volume":"86 ","pages":"Pages 124-134"},"PeriodicalIF":6.8,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142308103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Efficient utilization of xylose requires CO2 fixation in Synechococcus elongatus PCC 7942","authors":"Shannon R. Pressley,&nbsp;Jake N. Gonzales,&nbsp;Shota Atsumi","doi":"10.1016/j.ymben.2024.09.010","DOIUrl":"10.1016/j.ymben.2024.09.010","url":null,"abstract":"<div><div>Cyanobacteria show great promise as autotrophic hosts for the renewable biosynthesis of useful chemicals from CO₂ and light. While they can efficiently fix CO₂, cyanobacteria are generally outperformed by heterotrophic production hosts in terms of productivity and titer. Photomixotrophy, or co-utilization of sugars and CO₂ as carbon feedstocks, has been implemented in cyanobacteria to greatly improve productivity and titers of several chemical products. We introduced xylose photomixotrophy to a 2,3-butanediol producing strain of <em>Synechococcus elongatus</em> PCC 7942 and characterized the effect of gene knockouts, changing pathway expression levels, and changing growth conditions on chemical production. Interestingly, 2,3-butanediol production was almost completely inhibited in the absence of added CO₂. Untargeted metabolomics implied that RuBisCO was a significant bottleneck, especially at ambient CO₂ levels, restricting the supply of lower glycolysis metabolites needed for 2,3-butanediol production. The dependence of the strain on elevated CO₂ levels suggests some practical limitations on how xylose photomixotrophy can be efficiently carried out in <em>S. elongatus</em>.</div></div>","PeriodicalId":18483,"journal":{"name":"Metabolic engineering","volume":"86 ","pages":"Pages 115-123"},"PeriodicalIF":6.8,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1096717624001277/pdfft?md5=d948f70faeea495436d780992a7c5a88&pid=1-s2.0-S1096717624001277-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142308101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}