Biosynthesis pathway related production of medium chain length polyhydroxyalkanoates

Pseudomonas flava HBE06 isolated from oil-contaminated soil was found to produce polyesters consisting of medium chain length polyhydroxyalkanoates (mcl PHA). The strain mainly synthesized PHA containing 3-hydroxyoctanoate (C8 or HO), 3-hydroxynonanoate (C9 or HN), 3-hydroxydecanoate (C10 or HD), and 3-hydroxyunidecanoate (C11 or HUD) as monomers when grown on various substrates. It was found that the monomer ratio (especially C10 /C8 or C11 /C9) was related to the PHA biosynthesis pathway. When PHA was synthesized via the de novo fatty acid pathway, the molar ratio of C10 /C8was greater than 2. If PHA was synthesized from β-oxidation of fatty acids, C10 /C8was less than 1. Pseudomonas stutzeri 1317 is another mcl PHA synthesizing bacteria whose C10 /C8 ratio is also related to the synthesis pathway. When the two synthesis pathways were used together, the C10 /C8 ratio could be adjusted according to the ratio of the mixed substrates