Biosynthesis and Compositional Regulation of Poly[(3-hydroxybutyrate)-co-(3-hydroxyhexanoate)] in Recombinant Ralstonia eutropha Expressing Mutated Polyhydroxyalkanoate Synthase Genes

摘要

A new strategy for bacterial polyhydroxyalkanoate (PHA) production by recombinant Ralstonia eutropha PHB-4 harboring mutated PHA synthase genes (phaC_(Ac)) from Aeromona caviae was investigated. The strain harboring wild-type phaC_(Ac) gene produced a PHA copolymer consisting of (R)-3-hydroxybutyrate and (R)-3-hydroxyhexanoate [P(3HB-co-3HHx)] with 3.5 mol-% of 3HHx fraction from soybean oil. When the mutants of phaCAc gene were applied to this production system, 3HHx fraction in copolymers was varied in the range of 0-5.1 mol-%. Thus, the regulation of PHA copolymer compositions has been achieved by the use of mutated PHA synthase genes.