title: Biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P(HB-co-HHx)) from butyrate using engineered Ralstonia eutropha.
abstract: Polyhydroxyalkanoates (PHAs), a promising family of bio-based polymers, are considered to be alternatives to traditional petroleum-based plastics. Copolymers like poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P(HB-co-HHx)) have been shown to exhibit favorable physical and mechanical properties, due to decreased crystallinity resulting from the presence of medium-chain-length 3-hydroxyhexanoate (3HHx) monomers. In this study, we produced P(HB-co-HHx) using engineered Ralstonia eutropha strains containing deletions of the acetoacetyl-CoA reductase (phaB) genes and replacing the native PHA synthase with phaC2 from Rhodococcus aetherivorans I24 and by using butyrate, a short-chain organic acid, as the carbon source. Although the wild-type R. eutropha did not produce P(HB-co-HHx) when grown on mixed acids or on butyrate as the sole carbon source, we are able to produce polymer containing up to 40 wt% 3HHx monomer with the aforementioned engineered R. eutropha strains using various concentrations of just butyrate as the sole carbon source. This is the first report for the production of P(HB-co-HHx) copolymer in R. eutropha using butyrate.
authors.affiliation: Department of Microbial Engineering, College of Engineering, Konkuk University, Seoul, South Korea.
authors.forename: Jong-Min
authors.initials: JM
authors.lastname: Jeon
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Brigham
authors.forename: Yong-Hyun
authors.initials: YH
authors.lastname: Kim
authors.forename: Hyun-Joong
authors.initials: HJ
authors.lastname: Kim
authors.forename: Da-Hye
authors.initials: DH
authors.lastname: Yi
authors.forename: Hyungsup
authors.initials: H
authors.lastname: Kim
authors.forename: ChoKyun
authors.initials: C
authors.lastname: Rha
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Sinskey
authors.forename: Yung-Hun
authors.initials: YH
authors.lastname: Yang
mesh_terms: D020155:3-Hydroxybutyric Acid / Q000096:biosynthesis*; D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002087:Butyrates / Q000378:metabolism*; D002208:Caproates; D020118:Cupriavidus necator / Q000235:genetics* / Q000378:metabolism*; D060847:Metabolic Engineering; D000094122:Polyhydroxybutyrates
chemical_list: D020155:3-Hydroxybutyric Acid; D000217:Acyltransferases; D001426:Bacterial Proteins; D002087:Butyrates; D002208:Caproates; C115940:poly(3-hydroxybutyrate-co-3-hydroxyhexanoate); D000094122:Polyhydroxybutyrates; C077225:poly(3-hydroxyalkanoic acid) synthase