BIOSYNTHESIS OF POLYHYDROXYALKANOATES BY RHODOCISTA PEKINGENSIS / 微生物学通报

ABSTRACT

In this article we report the results on the synthesis and accumulation of PHAs by Rhodocista pekingensis (strain 3-p), a phototroph that was isolated from wastewater treatment plant. Our results showed that the optimal conditions for PHAs accumulation with strain 3-p were as following 0.01% Yeast Extract, 0.01% NH 4Cl, Acetate 5 g/L, and medium pH of 7.0～7.2.Under optimized conditions, strain 3-p accumulated PHAs up to 60% of its cellular dry weight. Enzymatic activities of ?-ketothiolase, acetoacetyl-CoA reductase, and PHA polymerase were detected and their activities increased as PHA synthesis initialized. Based on these study, we proposed the metabolic pathway of this strain should beAcetate (or other fatty acids) - Acetyl-CoA --- thiolase Acetoacetyl-CoA --- reductase D (-)-?-Hydroxybutyryl-CoA ----- PHA polymerase PHAs.