甲烷氧化细菌生物催化合成聚-β-羟基丁酸酯的分子量调控

Study on Molecular Weight of Poly-β-hydroxybutyrate Biosynthesized by Methylosinus Trichosporium IMV3011

在甲烷氧化细菌Methylosinus trichosporium IMV3011细胞内生物催化合成聚-β-羟基丁酸酯(PHB)的过程中,对影响聚合物分子量的各种因素进行了研究.发现碳源、培养基组分NH4+,NO3-,HPO24-,Mg2+,某些导向PHB合成的关键中间产物以及PHB的提取方法均会对PHB的分子量产生影响.同时,通过对胞内PHB合成酶系中关键作用酶的活性变化进行研究,发现β-酮硫解酶催化着控制进入PHB循环入口的关键反应,而PHB分子量的变化则主要取决于PHB合成酶和PHB降解酶的协同作用.

Influencing factors on the molecular weight of poly-β-hydroxybutyrate（PHB） synthesized by methanotrophic bacteria were studied.The carbon sources,the concentration of NH＋4,NO-3,HPO2-4,Mg2＋ in the culture medium,key intermediate in TCA cycle and different purification methods,have important effects on the molecular weight of PHB accumulated in the cells.Moreover,it was suggested that each key enzyme have their unique effects on PHB synthesized pathway by the study on the key enzymes activities in PHB metabolism.The molecular weight of PHB depended mainly on the combined effect of PHB synthetase and PHB depolymerase.