title: Biosynthesis of R-3-hydroxyalkanoic acids by metabolically engineered Escherichia coli.
abstract: An efficient system for the production of (R)-hydroxyalkanoic acids (RHAs) was developed in natural polyhydroxyalkanoate (PHA)-producing bacteria and recombinant Escherichia coli. Acidic alcoholysis of purified PHA and in vivo depolymerization of PHA accumulated in the cells allowed the production of RHAs. In recombinant E. coli, RHA production was achieved by removing CoA from (R)-3-hydroxyacyl-CoA and by in vivo depolymerization of PHA. When the recombinant E. coli harboring the Ralstonia eutropha PHA biosynthesis genes and the depolymerase gene was cultured in a complex or a chemically defined medium containing glucose, (R)-3-hydroxybutyric acid (R3HB) was produced as monomers and dimers. R3HB dimers could be efficiently converted to monomers by mild alkaline heat treatment. A stable recombinant E. coli strain in which the R. eutropha PHA biosynthesis genes were integrated into the chromosome disrupting the pta gene was constructed and examined for the production of R3HB. When the R. eutropha intracellular depolymerase gene was expressed by using a stable plasmid containing the hok/sok locus of plasmid R1, R3HB could be efficiently produced.
authors.affiliation: Metabolic and Biomolecular Engineering National Research Laboratory, Department of Chemical & Biomolecular Engineering, BioProcess Engineering Research Center, Republic of Korea.
authors.forename: Si Jae
authors.initials: SJ
authors.lastname: Park
authors.forename: Sang Yup
authors.initials: SY
authors.lastname: Lee
authors.forename: Young
authors.initials: Y
authors.lastname: Lee
mesh_terms: D000438:Alcohols / Q000737:chemistry; D001709:Biotechnology / Q000379:methods*; D020118:Cupriavidus necator / Q000235:genetics; D019281:Dimerization; D004926:Escherichia coli / Q000378:metabolism*; D005227:Fatty Acids / Q000737:chemistry; D005818:Genetic Engineering; D005947:Glucose / Q000737:chemistry; D006358:Hot Temperature; D006885:Hydroxybutyrates / Q000737:chemistry; D008954:Models, Biological; D010957:Plasmids / Q000378:metabolism; D011091:Polyesters
chemical_list: D000438:Alcohols; D005227:Fatty Acids; D006885:Hydroxybutyrates; D011091:Polyesters; D005947:Glucose