十溴联苯醚降解菌的特性及功能蛋白初步分析

筛选获得了1株对十溴联苯醚(BDE-209)有较好降解效率的菌株,经16S rRNA基因序列分析,初步鉴定为铅黄肠球菌(Enterococcus casseliflavus).该株菌最适培养条件为培养基初始pH 7,培养时间48 h.E.casseliflavus对BDE-209有较好的降解效果,在含有5 mg·L-1葡萄糖的降解体系中,1 g·L-1菌体处理1 mg·L-1BDE-209,4 d时降解率达到最大(56.7%).SDS-聚丙烯酰胺凝胶电泳实验结果表明,在E.casseliflavus降解BDE-209的过程中,2 mg·L-1与5 mg·L-1的BDE-209可诱导菌体生成某类新的胞外蛋白,而胞内蛋白则随着BDE-209含量的增加,表现为蛋白表达量的增减以及受BDE-209抑制而不表达某些蛋白质.双向电泳实验结果检测到31个差异点,表明在降解时菌体中与降解相关的蛋白构象发生了变化,导致蛋白种类和含量变化.

Characteristics and Functional Protein Analysis of an Effective Decabromodiphenyl Ether-Degrading Strain

An effective decabromodiphenyl ether (BDE-209) degrading strain was isolated and identified as Enterococcus casseliflavus based on the 16S rRNA gene sequence analysis. The optimal conditions for strain growth were pH 7 and culture time of 48 h, respectively. E. casseliflavus has a good ability to degrade BDE-209. The biodegradation rate of 1 mg·L^-1 BDE-209 by 1 g·L^-1 E. casseliflavus reached the highest of 56.7% after 4 days degradation with 5 mg·L^-1 glucose as the additional carbon source. During the degradation process of BDE-209, SDS-PAGE demonstrated that some new extracellular proteins were induced under 2 mg·L^-1 and 5 mg·L^-1 BDE-209. As for the intracellular proteins, the quantity of protein expression varied, and some proteins even disappeared compared with the blank control. Two-dimensional electrophoresis steps for protein analysis detected 31 different protein points, demonstrating that during the degradation process, the conformation of some proteins which were related with degradation was changed, and resulted in the variation of type and content of the proteins.