title: Improved artificial pathway for biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) with high C6-monomer composition from fructose in Ralstonia eutropha.
abstract: Poly((R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate) [P(3HB-co-3HHx)], a flexible and practical kind of polyhydroxyalkanoates, is generally produced from plant oils and fatty acids by several wild and recombinant bacteria. This study established an improved artificial pathway for the biosynthesis of P(3HB-co-3HHx) with high 3HHx composition from structurally unrelated fructose in Ralstonia eutropha. Depression of (R)-specific reduction of acetoacetyl-CoA by the deletion of phaB1 was an effective modification for formation of the C6-monomer unit from fructose driven by crotonyl-CoA carboxylase/reductase (Ccr). Co-overexpression of phaJ4a, which encodes medium-chain-length (R)-enoyl-CoA hydratase, with ccr promoted the incorporation of both 3HB and 3HHx units. Further introduction of emdMm, a synthetic gene encoding ethylmalonyl-CoA decarboxylase derived from mouse, was remarkably effective for P(3HB-co-3HHx) biosynthesis, probably by converting ethylmalonyl-CoA generated by the reductive carboxylase activity of Ccr back into butyryl-CoA. A high cellular content of P(3HB-co-3HHx) composed of 22mol% 3HHx could be produced from fructose by the engineered strain of R. eutropha with ΔphaB1 genotype expressing ccr, phaJ4a, and emd.
authors.affiliation: Department of Bioengineering, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: Chayatip
authors.initials: C
authors.lastname: Insomphun
authors.affiliation: Department of Bioengineering, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: Huan
authors.initials: H
authors.lastname: Xie
authors.affiliation: Department of Bioengineering, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Mifune
authors.affiliation: Department of Bioengineering, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: Yui
authors.initials: Y
authors.lastname: Kawashima
authors.affiliation: Department of Bioengineering, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: Izumi
authors.initials: I
authors.lastname: Orita
authors.affiliation: Department of Bioengineering, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nakamura
authors.affiliation: Department of Bioengineering, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan. Electronic address: tfukui@bio.titech.ac.jp.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Fukui
mesh_terms: D020155:3-Hydroxybutyric Acid / Q000096:biosynthesis* / Q000235:genetics; D000818:Animals; D002208:Caproates; D020118:Cupriavidus necator / Q000235:genetics / Q000378:metabolism*; D005632:Fructose / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D005798:Genes, Bacterial; D060847:Metabolic Engineering / Q000379:methods*; D051379:Mice; D000094122:Polyhydroxybutyrates
chemical_list: D020155:3-Hydroxybutyric Acid; D002208:Caproates; D005632:Fructose; C115940:poly(3-hydroxybutyrate-co-3-hydroxyhexanoate); D000094122:Polyhydroxybutyrates
keywords: Artificial pathway; Crotonyl-CoA carboxylase/reductase; Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate); Polyhydroxyalkanoates; Ralstonia eutropha