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

Abstract

Pseudomonas sp. PHA^- was used as host for PHA biosynthesis genes from Aeromonas sp. to produce 3HB-co-3HA_MCL from glucose with no supply of co-substrates. A non-naturally-occurring PHA composed mainly of 3HB, 3HHx and 3HD (3HO, 3HDdΔ₅ 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_MCL 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_MCL) production from carbohydrates as the sole carbon source.

Keywords: Aeromonas; Polyhydroxyalkanoates; Pseudomonas.