Production of heteropolymeric polyhydroxyalkanoate in Escherichia coli from a single carbon source.

Poly[beta-hydroxybutyrate-co-beta-hydroxyvalerate] co-polymer, PHBV, is a polyhydroxyalkanoate (PHA) that has greater utility as a biodegradable thermoplastic polyester than poly-beta-hydroxybutyrate, PHB. In order to produce PHBV, a system of pathways is required to produce both hydroxybutyrate (HB) and hydroxyvalerate (HV) monomers from the sources of carbon. A working model for conversion of glucose to PHBV via acetyl- and propionyl-coenzyme A was constructed by expressing the PHA biosynthesis genes from Alcaligenes eutrophus in Escherichia coli strain K-12 under novel growth conditions.

Saccharomyces cerevisiae expressing bacterial polyhydroxybutyrate synthase produces poly-3-hydroxybutyrate.

The polyhydroxybutyrate (PHB) synthase gene of the bacterium Alcaligenes eutrophus was used to construct a yeast plasmid which enabled expression of the functional synthase enzyme in Saccharomyces cerevisiae. Cells transformed with the synthase plasmid accumulated up to 0.5% of cell dry weight as PHB, with accumulation occurring in the stationary phase of batch growth.