研究报告

  • 刘莉莉,汪烯烯,陈鑫,周纯淳,唐周,林森.Methylobacterium sp.TP-1好氧降解四溴双酚A机理及其功能酶研究[J].环境科学学报,2018,38(11):4250-4258

  • Methylobacterium sp.TP-1好氧降解四溴双酚A机理及其功能酶研究
  • Studies on aerobic degradation mechanism of tetrabromobisphenol A and functional enzymes of Methylobacterium sp. TP-1
  • 基金项目:国家自然科学基金(No.41771513,41001316)
  • 作者
  • 单位
  • 刘莉莉
  • 华东理工大学资源与环境工程学院, 国家环境保护化工过程环境风险评价与控制重点实验室, 上海 200237
  • 汪烯烯
  • 华东理工大学资源与环境工程学院, 国家环境保护化工过程环境风险评价与控制重点实验室, 上海 200237
  • 陈鑫
  • 华东理工大学资源与环境工程学院, 国家环境保护化工过程环境风险评价与控制重点实验室, 上海 200237
  • 周纯淳
  • 华东理工大学资源与环境工程学院, 国家环境保护化工过程环境风险评价与控制重点实验室, 上海 200237
  • 唐周
  • 华东理工大学资源与环境工程学院, 国家环境保护化工过程环境风险评价与控制重点实验室, 上海 200237
  • 林森
  • 华东理工大学资源与环境工程学院, 国家环境保护化工过程环境风险评价与控制重点实验室, 上海 200237
  • 摘要:四溴双酚A (Tetrabromobisphenol A,TBBPA)是目前使用最广泛的溴代阻燃剂之一,在各种环境介质中普遍存在,对人体健康具有潜在危害.本研究从沉积物中筛选得到一株可降解TBBPA的菌株,命名为TP-1,经16S rDNA序列分析鉴定为甲基杆菌(Methylobacterium sp.).在pH=7的条件下反应60 h,菌株TP-1对初始浓度为10 mg·L-1的TBBPA降解率为74.87%.采用HPLC-MS测定TBBPA的降解产物,发现主要产物为二溴双酚A、双酚A、4-对羟基苯乙酮和二溴化芳香族化合物,其降解方式主要为β断裂、还原脱溴和氧化,进而初步推测出其降解途径.在此基础上,基于KEGG数据库分析菌株TP-1降解TBBPA的分子生物学机制,依据模拟降解途径和KEGG注释结果推测菌株TP-1降解TBBPA的功能酶为过氧化氢酶(EC:1.11.1.6)、卤代烷脱卤酶(EC:3.8.1.5)、卤乙酸脱卤酶(EC:3.8.1.3)和单加氧酶(EC:1.14.13.7).对这4种酶同源性和编码基因进行对比分析表明,这4种酶与甲基杆菌属菌株的相应功能酶均具有较高的同源性,且相应的基因簇在甲基杆菌属菌株中均具有较好的同线性,据此推测甲基杆菌属的多数菌株具有TBBPA降解能力.本研究可从分子水平阐述TBBPA的微生物降解机制,为相关研究提供有益参考.
  • Abstract:As one of the most widely used brominated flame retardants, tetrabromobisphenol A (TBBPA) is ubiquitous in environment, and potentially hazardous to human beings. In this study, a TBBPA-degrading strain was isolated from the sediment sample, named as TP-1, which was identified as Methylobacterium sp. according to 16S rDNA sequence. The experimental results show that the aerobic degradation efficiency of TBBPA by strain TP-1 could reach 74.87% in 60 h with the initial concentration of 10 mg·L-1 at pH 7. According to HPLC-MS analysis, it was confirmed that the major products of TBBPA were dibromobisphenol A, bisphenol A, 4-p-hydroxyacetophenone and dibrominated monoaromatic compounds, and the main degradation mechanisms are β-fragmentation, reductive debromination and oxidation. In addition, the molecular mechanism of TBPPA degradation by TP-1 was further analyzed with KEGG database. According to the simulated degradation pathway and KEGG annotation, the functional enzymes of strain TP-1 were assumed to be catalase (EC:1.11.1.6), haloalkane dehalogenase (EC:3.8.1.5), haloacetic acid dehalogenase (EC:3.8.1.3) and monooxygenase (EC:1.14.13.7). These enzymes have the highest orthology with the corresponding enzymes of Methylobacterium sp., and the gene cluster of the enzymes have the perfect synteny within Methylobacterium sp.. Therefore, it could be speculated that most strains within Methylobacterium sp. could degrade TBBPA. This study takes insight into the biodegradation of TBBPA at the molecular level, and provides the useful reference for related research.

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