SYNTHESIS OF POLY-(3-HYDROXYBUTYRATE-CO-3-HYDROXYVALERATE) BY RECOMBINANT ESCHERICHIA-COLI

Several recombinant Escherichia coli strains, including XL1-Blue, JM10 9, HB101, and DH5 alpha harboring a stable high-copynumber plasmid pSY L105 containing the Alcaligenes eutrophus polyhydroxyalkanoate (PHA) b iosynthesis genes were constructed. These recombinant strains were exa mined for their ability to synthesize and accumulate poly-(3-hydroxybu tyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] copolymer from glucose an d either propionate or valerate. All recombinant E. coil strains could synthesize the P(3HB-co-3HV) copolymer in the medium containing gluco se and propionate. However, only the homopolymer poly-(3-hydroxybutyra te) [P(BHB)] was synthesized from glucose and valerate. The PHA concen tration and the 3HV fraction could be increased by inducing with aceta te and/or oleate. When supplemented with oleate, the 3HV fraction incr eased by fourfold compared with that obtained without induction. Induc tion with propionate resulted in lower PHA concentration due to the in hibitory effect, but an 3HV fraction of as high as 33.0% could be obta ined. These results suggest that P(3HB-co-3HV) can be efficiently prod uced from propionate by recombinant 5. coli by inducing with acetate, propionate, or oleate. (C) 1996 John Wiley & Sons, Inc.