title: Production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with high molar fractions of 3-hydroxyvalerate by a threonine-overproducing mutant of Alcaligenes sp. SH-69.
abstract: A threonine overproducing mutant of Alcaligenes sp. SH-69 was isolated and its ability to produce poly(3-hydroxybutyrate-co-3-hydroxyvalerate), poly(3HB-co-3HV), was investigated. The 3HV fraction in poly(3HB-co-3HV) produced from glucose as the sole carbon source exceeded 22 mol%, which is approximately six times higher than that achieved by the wild type under the same culture conditions. Furthermore, the addition of a relatively low concentration (10 mM) of propionic acid, valeric acid or levulinic acid to the glucose medium greatly increased the molar fraction of 3HV in the copolyester, to 38-77 mol%. The results suggest that metabolic engineering of the biosynthetic pathways supplying polyhydroxyalkanoate monomers, such as the threonine biosynthetic pathway, can lead to new poly(3HB-co-3HV)-producing strains.
authors.affiliation: Department of Microbiology, Chungnam National University, Daejeon 305-764, Korea.
authors.forename: Gang Guk
authors.initials: GG
authors.lastname: Choi
authors.forename: Moo Woong
authors.initials: MW
authors.lastname: Kim
authors.forename: Jeong-Yoon
authors.initials: JY
authors.lastname: Kim
authors.forename: Young Ha
authors.initials: YH
authors.lastname: Rhee
mesh_terms: D000421:Alcaligenes / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D002478:Cells, Cultured; D015964:Gene Expression Regulation, Bacterial; D005818:Genetic Engineering / Q000379:methods*; D005947:Glucose / Q000378:metabolism; D007532:Isoleucine / Q000378:metabolism; D007982:Levulinic Acids / Q000494:pharmacology; D009154:Mutation; D010421:Pentanoic Acids / Q000494:pharmacology; D011091:Polyesters / Q000378:metabolism*; D011422:Propionates / Q000494:pharmacology; D013045:Species Specificity; D013379:Substrate Specificity; D013912:Threonine / Q000096:biosynthesis* / Q000235:genetics; D000094122:Polyhydroxybutyrates
chemical_list: D005947:Glucose; D007532:Isoleucine; D007982:Levulinic Acids; D010421:Pentanoic Acids; D011091:Polyesters; D011422:Propionates; D013912:Threonine; C052620:poly(3-hydroxybutyrate)-co-(3-hydroxyvalerate); D000094122:Polyhydroxybutyrates; C038780:n-pentanoic acid; C029658:propionic acid; C032246:levulinic acid