Biosynthesis of Random-Homo Block Copolymer Poly[Glycolate--3-Hydroxybutyrate (3HB)]--Poly(3HB) Using Sequence-Regulating Chimeric Polyhydroxyalkanoate Synthase in .

Glycolate (GL)-containing polyhydroxyalkanoate (PHA) was synthesized in expressing the engineered chimeric PHA synthase PhaC and coenzyme A transferase. The cells produced poly[GL--3-hydroxybutyrate (3HB)] with the supplementation of GL and 3HB, thus demonstrating that PhaC is the first known class I PHA synthase that is capable of incorporating GL units. The triad sequence analysis using H nuclear magnetic resonance indicated that the obtained polymer was composed of two distinct regions, a P(GL--3HB) random segment and P(3HB) homopolymer segment.

Influence of Unusual Co-substrates on the Biosynthesis of Medium-Chain-Length Polyhydroxyalkanoates Produced in Multistage Chemostat.

A two-stage chemostat cultivation was used to investigate the biosynthesis of functionalized medium-chain-length polyhydroxyalkanoate (mcl-PHA) in the β-oxidation weakened strain of KTQQ20. Chemostats were linked in sequence and allowed separation of biomass production in the first stage from the PHA synthesis in the second stage. Four parallel reactors in the second stage provided identical growth conditions and ensured that the only variable was the ratio of decanoic acid (C10) to an unusual PHA monomer precursor, such as 10-undecenoic acid (C11:1) or phenylvaleric acid (PhVA).