一株十溴联苯醚高效好氧降解菌的筛选、鉴定及降解特性

Screening, identification and characteristics of an effective decabromodiphenyl ether degrading aerobic strain

摘要:

【目的】从广东贵屿镇电子垃圾拆解地采集的沉积物样品中分离十溴联苯醚(BDE-209)高效好氧降解菌, 并考察其对BDE-209的降解特性。【方法】通过生理生化实验和16S rRNA测序鉴定菌种, 正交实验优化降解条件, 并分析不同降解体系及影响因素对菌降解BDE-209的影响。【结果】鉴定结果显示, 该BDE-209好氧降解菌为短短芽孢杆菌(Brevibacillus brevis)。B. brevis对1 mg/L BDE-209 5 d的降解率可达54.38%。正交实验结果表明, B. brevis降解BDE-209的最优条件为: pH 7, 投菌量3 g/L, 温度30 °C。降解特性研究结果显示B. brevis对BDE-209降解的最佳菌龄为36 h, 最佳氮源为(NH4)2SO4, B. brevis对Cu2+、Cd2+有较好的耐受性, 但Cu2+和Cd2+的存在会影响其对BDE-209的降解。当Cu2+浓度在1?5 mg/L, Cd2+浓度在0.3?0.5 mg/L范围内时, B. brevis对BDE-209降解均可达50%以上。【结论】B. brevis对BDE-209有很好的降解效率, 研究结果对BDE-209的好氧微生物降解及环境中BDE-209的生物修复具有较好的科学意义和应用价值。

关键词:十溴联苯醚, 微生物降解, 筛选, 重金属, 特性

Abstract:

[Objective] To isolate the aerobic strain with high-efficiency in degrading decabromodiphenyl ether (BDE-209) from sediment samples collected from Guiyu town in Guangdong Province, an e-waste recycling area, and investigate its degradation characteristics. [Methods] The strain was identified based on its physio-biochemical characteristics and 16S rRNA sequence analysis. The orthogonal experiment was conducted to determine the optimal degrading conditions, effects of different degradation systems and other factors on the degradation efficiency of the strain. [Results] The strain was identified as Brevibacillus brevis named as GY2. Its five-day degradation efficiency reached 54.38% when the initial concentration of BDE-209 was 1 mg/L. The optimum conditions for BDE-209 degradation were as follows: pH 7, bacterial dosage 3 g/L, and culturing temperature 30 °C. The study also showed that the optimal strain age was 36 h and the best nitrogen source was (NH4)2SO4. B. brevis could tolerate the toxicity of Cu2+ and Cd2+, although the presence of these heavy metals posed certain influence on BDE-209 degradation. As the concentration of Cu2+ and Cd2+ were in the range of 1?5 mg/L and 0.3?0.5 mg/L, respectively, the degradation efficiency of BDE-209 was still over 50%. [Conclusion] B. brevis is effective in degrading BDE-209, the results are of significance and application importance in the study of aerobic microbial degradation and environment bioremediation of BDE-209.

Key words:Decabromodiphenyl ethers, Microbial degradation, Screening, Heavy metal, Characteristics