A non-naturally-occurring P(3HB-co-3HA) is produced by recombinant Pseudomonas sp. from an unrelated carbon source.

Pseudomonas sp. PHA was used as host for PHA biosynthesis genes from Aeromonas sp. to produce 3HB-co-3HA from glucose with no supply of co-substrates. A non-naturally-occurring PHA composed mainly of 3HB, 3HHx and 3HD (3HO, 3HDdΔ and 3HDd monomers were detected in smaller amounts) was obtained. The polymer was extracted using two different solvents (acetone and chloroform) and subject to the following characterization tests: FTIR, DSC, TGA and GPC. The latter suggests a block copolymer since a single and narrow elution peak was observed for each sample. The DSC results ruled out the possibility of a random copolymer and agrees with a single copolymer composed of two blocks: one with the typical composition of PHA produced by Pseudomonas and another containing 3HB and 3HHx with a high 3HHx molar fraction. Thus, this study increases the perspectives of P(3HB-co-3HA) production from carbohydrates as the sole carbon source.