title: Metabolic engineering of Synechocystis sp. PCC 6803 for enhanced ethanol production based on flux balance analysis.
abstract: Synechocystis sp. PCC 6803 is an attractive host for bio-ethanol production due to its ability to directly convert atmospheric carbon dioxide into ethanol using photosystems. To enhance ethanol production in Synechocystis sp. PCC 6803, metabolic engineering was performed based on in silico simulations, using the genome-scale metabolic model. Comprehensive reaction knockout simulations by flux balance analysis predicted that the knockout of NAD(P)H dehydrogenase enhanced ethanol production under photoautotrophic conditions, where ammonium is the nitrogen source. This deletion inhibits the re-oxidation of NAD(P)H, which is generated by ferredoxin-NADP+reductase and imposes re-oxidation in the ethanol synthesis pathway. The effect of deleting the ndhF1 gene, which encodes NADH dehydrogenase subunit 5, on ethanol production was experimentally evaluated using ethanol-producing strains of Synechocystis sp. PCC 6803. The ethanol titer of the ethanol-producing ∆ndhF1 strain increased by 145%, compared with that of the control strain.
authors.affiliation: Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, 1-5 Yamadaoka, Suita, Osaka, 565-0871, Japan.
authors.forename: Katsunori
authors.initials: K
authors.lastname: Yoshikawa
authors.affiliation: Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, 1-5 Yamadaoka, Suita, Osaka, 565-0871, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Toya
authors.affiliation: Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, 1-5 Yamadaoka, Suita, Osaka, 565-0871, Japan. shimizu@ist.osaka-u.ac.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shimizu
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D000431:Ethanol / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D016680:Genome, Bacterial; D060847:Metabolic Engineering / Q000379:methods*; D008954:Models, Biological; D009252:NADPH Dehydrogenase / Q000235:genetics / Q000378:metabolism; D046939:Synechocystis / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D000431:Ethanol; D009252:NADPH Dehydrogenase
keywords: Ethanol production; Flux balance analysis; Genome-scale metabolic model; NdhF1 deletion; Synechocystis sp. PCC 6803