十溴联苯醚降解菌群的降解特性与组成分析

Characteristics and composition of the microbial consortium for decabromodiphenyl ether (BDE-209) degradation

摘要:

【目的】针对水体沉积物中日益严重的多溴联苯醚污染问题, 以电子垃圾污染河床沉积物为种源富集驯化获得的菌群Cf3, 研究该菌群对十溴联苯醚的降解特性以及其菌群结构组成。【方法】通过GC-MS分析十溴联苯醚降解后低溴代产物组成, 并测定其降解率; 通过DGGE技术分析了该BDE-209降解菌群的结构组成。【结果】菌群Cf3具有较强降解BDE-209的能力, 经过120 d的培养, 初始量为2.6 μmol的BDE-209降解率达到80.03%, OD600从0.01增长到0.21, pH由初始的6.93增加到反应结束时的8.50。菌群Cf3经过单菌落分离, 共获得10株可培养细菌, 通过16S rRNA基因序列比对发现, 其中6株与柠檬酸杆菌属(Citrobacter spp.)具有较高同源性, 其余4株与产碱杆菌属(Alcaligenes spp.)较相似。进一步采用DGGE分析菌群Cf3的结构组成时发现, 除了分离得到的2个菌属外, 该菌群中还含有拟杆菌属(Wolinella spp.)、氨基酸球菌属(Acidaminococcus spp.), 以及随着降解时间延长而消失的脱硫弧菌属(Desulfovibrio spp.)和醋杆菌属(Acetobacterium spp.)。【结论】获得了具有较强多溴联苯醚降解能力的菌群, 并分析了其降解特性和群落组成, 为进一步开展溴代阻燃剂等持久性有机污染物的生物修复提供宝贵的菌种资源和科学数据。

关键词:降解菌群, 十溴联苯醚, 生物降解, 群落组成

Abstract:

[Objective] A microbial consortium Cf3, which was obtained and enriched from an e-waste contaminated river sediment, was applied to study the characteristics for decabromodiphenyl ether (BDE-209) degradation in order to pave a way for the bioremediation of PBDEs contaminant in sediment. And the composition of the microbial consortium was also studied. [Methods] Congeners of BDE-209 after the biodegradation were analyzed by GC-MS and the degradation rates were calculated. the composition of the microbial consortium was analyzed by DGGE. [Results] High BDE-209 degradation rates were obtained by consortium Cf3. After 120 days incubation, 80.03% BDE-209 was transformed by consortium Cf3 when the initial amount of BDE-209 was 2.6 μmol. Meanwhile, the biomass was obtained and the OD600 value increased from 0.01 to 0.21. The pH also changed from 6.93 to 8.50 during the degradation process. Ten cultivable strains were isolated from this consortium, six of which associated with Citrobacter spp. and four with Alcaligenes spp. based on the 16S rRNA gene sequences. Denaturing gradient gel electrophoresis (DGGE) results showed that other four major genera Wolinella spp., Acidaminococcus spp., Acetobacterium spp. and Desulfovibrio spp. were presented besides Citrobacter spp. and Alcaligenes spp.. However, the bands for Acetobacterium spp. and Desulfovibrio spp. disappeared with prolonging the incubation time. [Conclusion] A microbial consortium with high PBDEs degradation rate was obtained. The data obtained in the study about the characteristics of the degradation of BDE-209 by the microbial consortium and the composition of the consortium could provides some useful information and precious strains resources for the anaerobic bioremediation of polybrominated diphenyl ethers (PBDEs) in the persistent organic polluted environment.

Key words:Degradation consortium, Decabromodiphenyl ether (BDE-209), biodegradation, microbial composition