title: Microbial production of R-3-hydroxybutyric acid by recombinant E. coli harboring genes of phbA, phbB, and tesB.
abstract: Production of R-3-hydroxybutyric acid (3HB) was observed when genes of beta-ketothiolase (PhbA), acetoacetyl CoA reductase (PhbB), and thioesterase II (TesB) were jointly expressed in Escherichia coli. TesB, generally regarded as a medium chain length acyl CoA thioesterase, was found, for the first time, to play an important role for transforming short chain length 3-hydroxybutyrate-CoA to its free fatty acid, namely, 3HB. E. coli BW25113 (pSPB01) harboring phbA, phbB, and tesB genes produced approximately 4 g/l 3HB in shake flask culture within 24 h with glucose used as a carbon source. Under anaerobic growth conditions, 3HB production was found to be more effective, achieving 0.47 g 3HB/g glucose compared with only 0.32 g 3HB/g glucose obtained from aerobic process. When growth was conducted on sodium gluconate, 6 g/l 3HB was obtained. In a 24-h fed-batch growth process conducted in a 6-l fermentor containing 3 l glucose mineral medium, 12 g/l 3HB was produced from 17 g/l cell dry weight (CDW). This was the highest 3HB productivity achieved by a one-stage fermentation process for 3HB production.
authors.affiliation: Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing, 100084, People's Republic of China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Liu
authors.forename: Shao-Ping
authors.initials: SP
authors.lastname: Ouyang
authors.forename: Ahleum
authors.initials: A
authors.lastname: Chung
authors.forename: Qiong
authors.initials: Q
authors.lastname: Wu
authors.forename: Guo-Qiang
authors.initials: GQ
authors.lastname: Chen
mesh_terms: D020155:3-Hydroxybutyric Acid / Q000378:metabolism*; D000102:Acetyl-CoA C-Acyltransferase / Q000235:genetics / Q000378:metabolism*; D000429:Alcohol Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D001709:Biotechnology / Q000379:methods*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D064429:Fatty Acid Synthases / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D013056:Spectrophotometry, Ultraviolet; D013869:Thiolester Hydrolases / Q000235:genetics / Q000378:metabolism*
chemical_list: D011994:Recombinant Proteins; D000429:Alcohol Oxidoreductases; C023744:acetoacetyl-CoA reductase; D000102:Acetyl-CoA C-Acyltransferase; D064429:Fatty Acid Synthases; D013869:Thiolester Hydrolases; C022738:thioesterase II; D020155:3-Hydroxybutyric Acid