【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。
[Objective] To isolate the aerobic strain with high-efficiency in degrading decab- romodiphenyl ether (BDE-209) from sediment samples collected from Guiyu town in Guang- dong 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 degra- dation 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 concentra- tion of BDE-209 was 1 mg/L. The optimum conditions for BDE-209 degradation were as fol- lows: pH 7, bacterial dosage 3 g/L, and culturing temperature 30 ℃. 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 en- vironment bioremediation of BDE-209.