RESUMO
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 be:Acetate (or other fatty acids) - Acetyl-CoA --- thiolase Acetoacetyl-CoA --- reductase D (-)-?-Hydroxybutyryl-CoA ----- PHA polymerase PHAs.