四溴双酚A好氧降解菌的筛选及其降解特性研究

Isolation of Aerobic Degrading Strains for TBBPA and the Properties of Biodegradation

为了解四溴双酚A(TBBPA)的微生物降解特性,采用TBBPA为单一碳源的选择性培养基从苯酚降解颗粒污泥中筛选出4株对TBBPA具有良好降解性的好氧菌株,其中菌株H经16S rDNA测序鉴定为红球菌属.正交试验得出其最优降解条件为:温度30℃,摇床转速150 r.min-1,pH 6.5,腐殖酸浓度200 mg·L-1,K+浓度1 000 mg·L-1;此条件下21 d降解脱溴率达20.75%.LC-MS结果表明,TBBPA好氧降解的主要产物是分子中异丙基与苯环断裂后脱溴产生的一溴苯酚.聚丙烯酰胺蛋白凝胶电泳(SDS-PAGE)结果表明,该菌株H的蛋白系列中含有一条介于(90～117)×103间的条带,对比同期考察的葡萄糖培养与TBBPA无机盐溶液培养菌,结合粗酶液的降解实验,该蛋白可能是受TBBPA激活的特异性降解酶.

In order to investigate the characteristics of the microbial degradation of tetrabromobisphenol A（TBBPA）,four aerobic strains were isolated from the phenol granular sludge using selective medium with TBBPA as the sole carbon source.Among them,strain H could accommodate the TBBPA culture medium and degrade TBBPA with high efficiency,which was identified as Rhodococcus sp.via DNA sequencing test.The optimal conditions for TBBPA degradation by strain H was pH 6.5,30℃,150 r·min^-1,the concentration of humic acid being 200 mg·L^-1 and the concentration of K＋ being 1 000 mg·L^-1.Under the optimal conditions,the debromination rate of TBBPA reached 20.75% after 21 d.The results of LC-MS showed that the major degradation product was monobromophenol,which was formed by the removal of isopropyl from the benzene ring in TBBPA molecule.The results of protein gel electrophoresis（SDS-PAGE） showed that strain H had a protein band between（90-117）×10^3 kDa,which might be the enzyme responsible for TBBPA degradation.