Metabolic Engineering Communications最新文献

{"title":"Characterization and engineering of the xylose-inducible xylP promoter for use in mold fungal species","authors":"Annie Yap ,&nbsp;Irene Glarcher ,&nbsp;Matthias Misslinger,&nbsp;Hubertus Haas","doi":"10.1016/j.mec.2022.e00214","DOIUrl":"https://doi.org/10.1016/j.mec.2022.e00214","url":null,"abstract":"<div><p>Conditional promoters allowing both induction and silencing of gene expression are indispensable for basic and applied research. The <em>xylP</em> promoter (p<em>xylP</em>) from <em>Penicillium chrysogenum</em> was demonstrated to function in various mold species including <em>Aspergillus fumigatus</em>. p<em>xylP</em> allows high induction by xylan or its degradation product xylose with low basal activity in the absence of an inducer. Here we structurally characterized and engineered p<em>xylP</em> in <em>A. fumigatus</em> to optimize its application. Mutational analysis demonstrated the importance of the putative TATA-box and a pyrimidine-rich region in the core promoter, both copies of a largely duplicated 91-bp sequence (91bpDS), as well as putative binding sites for the transcription factor XlnR and a GATA motif within the 91bpDS. In agreement, p<em>xylP</em> activity was found to depend on XlnR, while glucose repression appeared to be indirect. Truncation of the originally used 1643-bp promoter fragment to 725 bp largely preserved the promoter activity and the regulatory pattern. Integration of a third 91bpDS significantly increased promoter activity particularly under low inducer concentrations. Truncation of p<em>xylP</em> to 199 bp demonstrated that the upstream region including the 91bpDSs mediates not only inducer-dependent activation but also repression in the absence of inducer. Remarkably, the 1579-bp p<em>xylP</em> was found to act bi-bidirectionally with a similar regulatory pattern by driving expression of the upstream-located arabinofuranosidase gene. The latter opens the possibility of dual bidirectional use of p<em>xylP</em>. Comparison with a doxycycline-inducible TetOn system revealed a significantly higher dynamic range of p<em>xylP</em>. Taken together, this study identified functional elements of p<em>xylP</em> and opened new methodological opportunities for its application.</p></div>","PeriodicalId":18695,"journal":{"name":"Metabolic Engineering Communications","volume":"15 ","pages":"Article e00214"},"PeriodicalIF":5.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2214030122000232/pdfft?md5=43a616ce871d93dcd430b7cbcb1a7779&pid=1-s2.0-S2214030122000232-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89988962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Metabolic engineering of Pseudomonas taiwanensis VLB120 for rhamnolipid biosynthesis from biomass-derived aromatics","authors":"Vaishnavi Sivapuratharasan ,&nbsp;Christoph Lenzen ,&nbsp;Carina Michel ,&nbsp;Anantha Barathi Muthukrishnan ,&nbsp;Guhan Jayaraman ,&nbsp;Lars M. Blank","doi":"10.1016/j.mec.2022.e00202","DOIUrl":"https://doi.org/10.1016/j.mec.2022.e00202","url":null,"abstract":"<div><p>Lignin is a ubiquitously available and sustainable feedstock that is underused as its depolymerization yields a range of aromatic monomers that are challenging substrates for microbes. In this study, we investigated the growth of <em>Pseudomonas taiwanensis</em> VLB120 on biomass-derived aromatics, namely, 4-coumarate, ferulate, 4-hydroxybenzoate, and vanillate. The wild type strain was not able to grow on 4-coumarate and ferulate. After integration of catabolic genes for breakdown of 4-coumarate and ferulate, the metabolically engineered strain was able to grow on these aromatics. Further, the specific growth rate of the strain was enhanced up to 3-fold using adaptive laboratory evolution, resulting in increased tolerance towards 4-coumarate and ferulate. Whole-genome sequencing highlighted several different mutations mainly in two genes. The first gene was <em>actP</em>, coding for a cation/acetate symporter, and the other gene was <em>paaA</em> coding for a phenyl acetyl-CoA oxygenase. The evolved strain was further engineered for rhamnolipid production. Among the biomass-derived aromatics investigated, 4-coumarate and ferulate were promising substrates for product synthesis. With 4-coumarate as the sole carbon source, a yield of 0.27 (Cmol_rhl/Cmol_4-coumarate) was achieved, corresponding to 28% of the theoretical yield. Ferulate enabled a yield of about 0.22 (Cmol_rhl/Cmol_ferulate), representing 42% of the theoretical yield. Overall, this study demonstrates the use of biomass-derived aromatics as novel carbon sources for rhamnolipid biosynthesis.</p></div>","PeriodicalId":18695,"journal":{"name":"Metabolic Engineering Communications","volume":"15 ","pages":"Article e00202"},"PeriodicalIF":5.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2214030122000116/pdfft?md5=29575c540fc6b7e0e6bf633a82266d60&pid=1-s2.0-S2214030122000116-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89989006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heterologous phasin expression in Rhodopseudomonas palustris CGA009 for bioplastic production from lignocellulosic biomass","authors":"Brandi Brown ,&nbsp;Cheryl Immethun ,&nbsp;Adil Alsiyabi ,&nbsp;Dianna Long ,&nbsp;Mark Wilkins ,&nbsp;Rajib Saha","doi":"10.1016/j.mec.2021.e00191","DOIUrl":"https://doi.org/10.1016/j.mec.2021.e00191","url":null,"abstract":"<div><p><em>Rhodopseudomonas palustris</em> CGA009 is a metabolically robust microbe that can utilize lignin breakdown products to produce polyhydroxyalkanoates (PHAs), biopolymers with the potential to replace conventional plastics. Our recent efforts suggest PHA granule formation is a limiting factor for maximum production of the bioplastic poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) by <em>R. palustris.</em> The Phap1 phasin (<em>phaP1</em>) from the PHB-producing model bacterium <em>Cupriavidus necator</em> H16 was expressed in <em>R. palustris</em> with the aim of overproducing PHBV from the lignin breakdown product <em>p-</em>coumarate by fostering smaller and more abundant granules. Expression of <em>phaP1</em> yielded PHBV production from <em>R. palustris</em> aerobically (0.7 g/L), which does not occur in the wild-type strain, and led to a significantly higher PHBV titer than wild-type anaerobic production (0.41 g/L). The 3HV fractions were also significantly increased under both anaerobic and aerobic conditions, which boosts thermomechanical properties and potential for application. Thus, heterologous phasin expression in <em>R. palustris</em> provides flexibility for industrial processing and could foster compositional changes in copolymers with better thermomechanical properties compared to PHB alone.</p></div>","PeriodicalId":18695,"journal":{"name":"Metabolic Engineering Communications","volume":"14 ","pages":"Article e00191"},"PeriodicalIF":5.2,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2214030121000316/pdfft?md5=ff323c34605bef32932c28358858dc3e&pid=1-s2.0-S2214030121000316-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92014806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of metabolic engineering to enhance the content of alkaloids in medicinal plants","authors":"Soledad Mora-Vásquez ,&nbsp;Guillermo Gael Wells-Abascal ,&nbsp;Claudia Espinosa-Leal ,&nbsp;Guy A. Cardineau ,&nbsp;Silverio García-Lara","doi":"10.1016/j.mec.2022.e00194","DOIUrl":"10.1016/j.mec.2022.e00194","url":null,"abstract":"<div><p>Plants are a rich source of bioactive compounds, many of which have been exploited for cosmetic, nutritional, and medicinal purposes. Through the characterization of metabolic pathways, as well as the mechanisms responsible for the accumulation of secondary metabolites, researchers have been able to increase the production of bioactive compounds in different plant species for research and commercial applications. The intent of the current review is to describe the metabolic engineering methods that have been used to transform in vitro or field-grown medicinal plants over the last decade and to identify the most effective approaches to increase the production of alkaloids. The articles summarized were categorized into six groups: endogenous enzyme overexpression, foreign enzyme overexpression, transcription factor overexpression, gene silencing, genome editing, and co-overexpression. We conclude that, because of the complex and multi-step nature of biosynthetic pathways, the approach that has been most commonly used to increase the biosynthesis of alkaloids, and the most effective in terms of fold increase, is the co-overexpression of two or more rate-limiting enzymes followed by the manipulation of regulatory genes.</p></div>","PeriodicalId":18695,"journal":{"name":"Metabolic Engineering Communications","volume":"14 ","pages":"Article e00194"},"PeriodicalIF":5.2,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8881666/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46036667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Control of D-lactic acid content in P(LA-3HB) copolymer in the yeast Saccharomyces cerevisiae using a synthetic gene expression system","authors":"Anna Ylinen ,&nbsp;Laura Salusjärvi ,&nbsp;Mervi Toivari ,&nbsp;Merja Penttilä","doi":"10.1016/j.mec.2022.e00199","DOIUrl":"10.1016/j.mec.2022.e00199","url":null,"abstract":"<div><p>The fully biobased polyhydroxyalkanoate (PHA) polymers provide interesting alternatives for petrochemical derived plastic materials. The mechanical properties of some PHAs, including the common poly(3-hydroxybutyrate) (PHB), are limited, but tunable by addition of other monomers into the polymer chain. In this study we present a precise synthetic biology method to adjust lactate monomer fraction of a polymer by controlling the monomer formation <em>in vivo</em> at gene expression level, independent of cultivation conditions. We used the modified doxycycline-based Tet-On approach to adjust the expression of the stereospecific D-lactate dehydrogenase gene (<em>ldhA</em>) from <em>Leuconostoc mesenteroides</em> to control D-lactic acid formation in yeast <em>Saccharomyces cerevisiae</em>. The synthetic Tet-On transcription factor with a VP16 activation domain was continuously expressed and its binding to a synthetic promoter with eight transcription factor specific binding sites upstream of the <em>ldhA</em> gene was controlled with the doxycycline concentration in the media. The increase in doxycycline concentration correlated positively with <em>ldhA</em> expression, D-lactic acid production, poly(D-lactic acid) (PDLA) accumulation <em>in vivo</em>, and D-lactic acid content in the poly(D-lactate-<em>co</em>-3-hydroxybutyrate) P(LA-3HB) copolymer. We demonstrated that the D-lactic acid content of the P(LA-3HB) copolymer can be adjusted linearly from 6 mol% to 93 mol% <em>in vivo</em> in <em>S. cerevisiae</em>. These results highlight the power of controlling gene expression and monomer formation in the tuning of the polymer composition. In addition, we obtained 5.6% PDLA and 19% P(LA-3HB) of the cell dry weight (CDW), which are over two- and five-fold higher accumulation levels, respectively, than reported in the previous studies with yeast. We also compared two engineered PHA synthases and discovered that in <em>S. cerevisiae</em> the PHA synthase PhaC1437_Ps6-19 produced P(LA-3HB) copolymers with lower D-lactic acid content, but with higher molecular weight, in comparison to the PHA synthase PhaC1Pre.</p></div>","PeriodicalId":18695,"journal":{"name":"Metabolic Engineering Communications","volume":"14 ","pages":"Article e00199"},"PeriodicalIF":5.2,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2214030122000086/pdfft?md5=46cba499ea94cf885917415684ffaf00&pid=1-s2.0-S2214030122000086-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46506594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Engineering of Yarrowia lipolytica for the production of plant triterpenoids: Asiatic, madecassic, and arjunolic acids","authors":"Jonathan Asmund Arnesen ,&nbsp;Arian Belmonte Del Ama ,&nbsp;Sidharth Jayachandran ,&nbsp;Jonathan Dahlin ,&nbsp;Daniela Rago ,&nbsp;Aaron John Christian Andersen ,&nbsp;Irina Borodina","doi":"10.1016/j.mec.2022.e00197","DOIUrl":"10.1016/j.mec.2022.e00197","url":null,"abstract":"<div><p>Several plant triterpenoids have valuable pharmaceutical properties, but their production and usage is limited since extraction from plants can burden natural resources, and result in low yields and purity. Here, we engineered oleaginous yeast <em>Yarrowia lipolytica</em> to produce three valuable plant triterpenoids (asiatic, madecassic, and arjunolic acids) by fermentation. First, we established the recombinant production of precursors, ursolic and oleanolic acids, by expressing plant enzymes in free or fused versions in a <em>Y. lipolytica</em> strain previously optimized for squalene production. Engineered strains produced up to 11.6 mg/g DCW ursolic acid or 10.2 mg/g DCW oleanolic acid. The biosynthetic pathway from ursolic acid was extended by expressing the <em>Centella asiatica</em> cytochrome P450 monoxygenases CaCYP716C11p, CaCYP714E19p, and CaCYP716E41p, resulting in the production of trace amounts of asiatic acid and 0.12 mg/g DCW madecassic acid. Expressing the same <em>C. asiatica</em> cytochromes P450 in oleanolic acid-producing strain resulted in the production of oleanane triterpenoids. Expression of CaCYP716C11p in the oleanolic acid-producing strain yielded 8.9 mg/g DCW maslinic acid. Further expression of a codon-optimized CaCYP714E19p resulted in 4.4 mg/g DCW arjunolic acid. Lastly, arjunolic acid production was increased to 9.1 mg/g DCW by swapping the N-terminal domain of CaCYP714E19p with the N-terminal domain from a <em>Kalopanax septemlobus</em> cytochrome P450. In summary, we have demonstrated the production of asiatic, madecassic, and arjunolic acids in a microbial cell factory. The strains and fermentation processes need to be further improved before the production of these molecules by fermentation can be industrialized.</p></div>","PeriodicalId":18695,"journal":{"name":"Metabolic Engineering Communications","volume":"14 ","pages":"Article e00197"},"PeriodicalIF":5.2,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2214030122000062/pdfft?md5=b0e2d3e79a3561fa2b0e6e7978810d74&pid=1-s2.0-S2214030122000062-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43852633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In vivo production of pederin by labrenzin pathway expansion","authors":"Dina Kačar ,&nbsp;Carmen Schleissner ,&nbsp;Librada M. Cañedo ,&nbsp;Pilar Rodríguez ,&nbsp;Fernando de la Calle ,&nbsp;Carmen Cuevas ,&nbsp;Beatriz Galán ,&nbsp;José Luis García","doi":"10.1016/j.mec.2022.e00198","DOIUrl":"https://doi.org/10.1016/j.mec.2022.e00198","url":null,"abstract":"<div><p>Pederin is a potent polyketide toxin that causes severe skin lesions in humans after contact with insects of genus <em>Paederus.</em> Due to its potent anticancer activities, pederin family compounds have raised the interest of pharmaceutical industry. Despite the extensive studies on the cluster of biosynthetic genes responsible for the production of pederin, it has not yet been possible to isolate and cultivate its bacterial endosymbiont producer. However, the marine bacterium <em>Labrenzia</em> sp. PHM005 was recently reported to produce labrenzin, the closest pederin analog. By cloning a synthetic <em>pedO</em> gene encoding one of the three <em>O</em>-methyltraferase of the pederin cluster into <em>Labrenzia</em> sp. PHM005 we have been able to produce pederin for the first time by fermentation in the new recombinant strain.</p></div>","PeriodicalId":18695,"journal":{"name":"Metabolic Engineering Communications","volume":"14 ","pages":"Article e00198"},"PeriodicalIF":5.2,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2214030122000074/pdfft?md5=5dd8f3cd4cbadeb5d281286c91f9e536&pid=1-s2.0-S2214030122000074-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91985337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of an E. coli-based norbaeocystin production platform and evaluation of behavioral effects in rats","authors":"Alexandra M. Adams ,&nbsp;Nicholas A. Anas ,&nbsp;Abhishek K. Sen ,&nbsp;Jordan D. Hinegardner-Hendricks ,&nbsp;Philip J. O’Dell ,&nbsp;William J. Gibbons Jr. ,&nbsp;Jessica E. Flower ,&nbsp;Matthew S. McMurray ,&nbsp;J. Andrew Jones","doi":"10.1016/j.mec.2022.e00196","DOIUrl":"https://doi.org/10.1016/j.mec.2022.e00196","url":null,"abstract":"<div><p>Interest in the potential therapeutic efficacy of psilocybin and other psychedelic compounds has escalated significantly in recent years. To date, little is known regarding the biological activity of the psilocybin pathway intermediate, norbaeocystin, due to limitations around sourcing the phosphorylated tryptamine metabolite for <em>in vivo</em> testing. To address this limitation, we first developed a novel <em>E. coli</em> platform for the rapid and scalable production of gram-scale amounts of norbaeocystin. Through this process we compare the genetic and fermentation optimization strategies to that of a similarly constructed and previously reported psilocybin producing strain, uncovering the need for reoptimization and balancing upon even minor genetic modifications to the production host. We then perform <em>in vivo</em> measurements of head twitch response to both biosynthesized psilocybin and norbaeocystin using both a cell broth and water vehicle in Long-Evans rats. The data show a dose response to psilocybin while norbaeocystin does not elicit any pharmacological response, suggesting that norbaeocystin and its metabolites may not have a strong affinity for the serotonin 2A receptor. The findings presented here provide a mechanism to source norbaeocystin for future studies to evaluate its disease efficacy in animal models, both individually and in combination with psilocybin, and support the safety of cell broth as a drug delivery vehicle.</p></div>","PeriodicalId":18695,"journal":{"name":"Metabolic Engineering Communications","volume":"14 ","pages":"Article e00196"},"PeriodicalIF":5.2,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2214030122000050/pdfft?md5=9e357069270222eb1ebc39ece357e30f&pid=1-s2.0-S2214030122000050-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92108344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Production of human milk fat substitute by engineered strains of Yarrowia lipolytica","authors":"Govindprasad Bhutada ,&nbsp;Guillaume Menard ,&nbsp;Rupam Kumar Bhunia ,&nbsp;Piotr P. Hapeta ,&nbsp;Rodrigo Ledesma-Amaro ,&nbsp;Peter J. Eastmond","doi":"10.1016/j.mec.2022.e00192","DOIUrl":"https://doi.org/10.1016/j.mec.2022.e00192","url":null,"abstract":"<div><p>Human milk fat has a distinctive stereoisomeric structure where palmitic acid is esterified to the middle (sn-2) position on the glycerol backbone of the triacylglycerol and unsaturated fatty acids to the outer (sn-1/3) positions. This configuration allows for more efficient nutrient absorption in the infant gut. However, the fat used in most infant formulas originates from plants, which exclude palmitic acid from the sn-2 position. Oleaginous yeasts provide an alternative source of lipids for human nutrition. However, these yeasts also exclude palmitic acid from the sn-2 position of their triacylglycerol. Here we show that <em>Yarrowia lipolytica</em> can be engineered to produce triacylglycerol with more than 60% of the palmitic acid in the sn-2 position, by expression of lysophosphatidic acid acyltransferases with palmitoyl-Coenzyme A specificity. The engineered <em>Y. lipolytica</em> strains can be cultured on glycerol, glucose, palm oil or a mixture of substrates, under nitrogen limited condition, to produce triacylglycerol with a fatty acid composition that resembles human milk fat, in terms of the major molecular species (palmitic, oleic and linoleic acids). Culture on palm oil or a mixture of glucose and palm oil produced the highest lipid titre and a triacylglycerol composition that is most similar with human milk fat. Our data show that an oleaginous yeast can be engineered to produce a human milk fat substitute (β-palmitate), that could be used as an ingredient in infant formulas.</p></div>","PeriodicalId":18695,"journal":{"name":"Metabolic Engineering Communications","volume":"14 ","pages":"Article e00192"},"PeriodicalIF":5.2,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2214030122000013/pdfft?md5=b439d333179d8ed71d63845cd095cde2&pid=1-s2.0-S2214030122000013-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92014805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermodynamics contributes to high limonene productivity in cyanobacteria","authors":"Shrameeta Shinde ,&nbsp;Sonali Singapuri ,&nbsp;Zhenxiong Jiang ,&nbsp;Bin Long ,&nbsp;Danielle Wilcox ,&nbsp;Camille Klatt ,&nbsp;J. Andrew Jones ,&nbsp;Joshua S. Yuan ,&nbsp;Xin Wang","doi":"10.1016/j.mec.2022.e00193","DOIUrl":"10.1016/j.mec.2022.e00193","url":null,"abstract":"<div><p>Terpenoids are a large group of secondary metabolites with broad industrial applications. Engineering cyanobacteria is an attractive route for the sustainable production of commodity terpenoids. Currently, a major obstacle lies in the low productivity attained in engineered cyanobacterial strains. Traditional metabolic engineering to improve pathway kinetics has led to limited success in enhancing terpenoid productivity. In this study, we reveal thermodynamics as the main determinant for high limonene productivity in cyanobacteria. Through overexpressing the primary sigma factor, a higher photosynthetic rate was achieved in an engineered strain of S<em>ynechococcus elongatus</em> PCC 7942. Computational modeling and wet lab analyses showed an increased flux toward both native carbon sink glycogen synthesis and the non-native limonene synthesis from photosynthate output. On the other hand, comparative proteomics showed decreased expression of terpene pathway enzymes, revealing their limited role in determining terpene flux. Lastly, growth optimization by enhancing photosynthesis has led to a limonene titer of 19 mg/L in 7 days with a maximum productivity of 4.3 mg/L/day. This study highlights the importance of enhancing photosynthesis and substrate input for the high productivity of secondary metabolic pathways, providing a new strategy for future terpenoid engineering in phototrophs.</p></div>","PeriodicalId":18695,"journal":{"name":"Metabolic Engineering Communications","volume":"14 ","pages":"Article e00193"},"PeriodicalIF":5.2,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/6c/fd/main.PMC8801761.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39908234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}