title: Propionyl-CoA dependent biosynthesis of 2-hydroxybutyrate containing polyhydroxyalkanoates in metabolically engineered Escherichia coli.
abstract: We have previously reported in vivo biosynthesis of 2-hydroxyacid containing polyesters including polylactic acid (PLA), poly(3-hydroxybutyrate-co-lactate) [P(3HB-co-LA)], and poly(3-hydroxybutyrate-co-2-hydroxybutyrate-co-lactate) [P(3HB-co-2HB-co-LA)] employing metabolically engineered Escherichia coli strains by the introduction of evolved Clostridium propionicum propionyl-CoA transferase (Pct(Cp)) and Pseudomonas sp. MBEL 6-19 polyhydroxyalkanoate (PHA) synthase 1 (PhaC1(Ps6-19)). In this study, we further engineered in vivo PLA biosynthesis system in E. coli to synthesize 2HB-containing PHA, in which propionyl-CoA was used as precursor for 2-ketobutyrate that was converted into 2HB-CoA by the sequential actions of Lactococcus lactis (D)-2-hydroxybutyrate dehydrogenase (PanE) and Pct(Cp) and then 2HB-CoA was polymerized by PhaC1(Ps6-19). The recombinant E. coli XL1-blue expressing the phaC1437 gene, the pct540 gene, and the Ralstonia eutropha prpE gene together with the panE gene could be grown to 0.66 g/L and successfully produced P(70 mol%3HB-co-18 mol%2HB-co-12 mol%LA) up to the PHA content of 66 wt% from 20 g/L of glucose, 2 g/L of 3HB and 1 g/L of sodium propionate. Removal of the prpC gene in the chromosome of E. coli XL1-blue could increase the mole fraction of 2HB in copolymer, but the PHA content was decreased. The metabolic engineering strategy reported here suggests that propionyl-CoA can be successfully used as the precursor to provide PHA synthase with 2HB-CoA for the production of PHAs containing 2HB monomer.
authors.affiliation: Department of Environmental Engineering and Energy-Undergraduate Program, Myongji University, San 38-2, Nam-dong, Cheoin-gu, Yongin-si, Gyeonggido 449-728, Republic of Korea.
authors.forename: Si Jae
authors.initials: SJ
authors.lastname: Park
authors.forename: Kyoung-Hee
authors.initials: KH
authors.lastname: Kang
authors.forename: Hyuk
authors.initials: H
authors.lastname: Lee
authors.forename: A-Reum
authors.initials: AR
authors.lastname: Park
authors.forename: Jung Eun
authors.initials: JE
authors.lastname: Yang
authors.forename: Young Hoon
authors.initials: YH
authors.lastname: Oh
authors.forename: Bong Keun
authors.initials: BK
authors.lastname: Song
authors.forename: Jonggeon
authors.initials: J
authors.lastname: Jegal
authors.forename: Seung Hwan
authors.initials: SH
authors.lastname: Lee
authors.forename: Sang Yup
authors.initials: SY
authors.lastname: Lee
mesh_terms: D000214:Acyl Coenzyme A / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism*; D006885:Hydroxybutyrates / Q000378:metabolism*; D054813:Polyhydroxyalkanoates / Q000378:metabolism*
chemical_list: D000214:Acyl Coenzyme A; D006885:Hydroxybutyrates; D054813:Polyhydroxyalkanoates; C009061:propionyl-coenzyme A