北京红篓菌合成聚羟基烷酸的研究

BIOSYNTHESIS OF POLYHYDROXYALKANOATES BY RHODOCISTA PEKINGENSIS

报道从污水处理厂回流池废水中分离到的北京红篓菌 (Rcs.pekingensisstrain 3 p)合成PHAs的研究结果。实验结果表明 ,3 p菌株生长及积累PHAs的最佳培养条件为 :0 0 1 %酵母膏 ,0 0 1 %NH4 Cl,乙酸钠 5g L ;培养基最适pH值为 7 0～ 7 2。在此培养条件下 ,细胞内PHAs积累量达菌体干重的 60 %以上。酶活测定表明菌株 3 p含有与PHAs合成相关的β 酮硫解酶 ,乙酰乙酰CoA还原酶 ,PHA聚合酶 ,初步推断此菌株的代谢途径为 :乙酸 (或其他脂肪酸 )—乙酰CoA—乙酰乙酰CoA—羟基丁酰CoA—PHAs。

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 β-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 (-)-β-Hydroxybutyryl-CoA ----- PHA polymerase PHAs.