联苯菊酯降解菌株BF-3的分离筛选、鉴定和降解特性

【背景】联苯菊酯是人工合成的类似天然除虫菊素的一种仿生杀虫剂，近年来被广泛应用于农业病虫害的防治。联苯菊酯化学性质较稳定，在环境中的残留期长，是我国出口果蔬、茶叶中残留较严重的农药之一。微生物降解具有降解速度快、无二次污染等优点，被认为是有效去除农药残留的绿色生产技术。【方法】通过富集驯化，从农药厂排污口的污泥中筛选分离能够降解联苯菊酯的菌株，经形态学观察、生理生化特性测定及16SrRNA序列分析对其进行鉴定，通过单因素试验对菌株的降解特性进行研究。【结果】分离到1株联苯菊酯的降解菌株BF-3。菌株BF-3为革兰氏阳性菌，被鉴定为蜡状芽孢杆菌；该菌株在联苯菊酯质量浓度为100mg·L^-1的无机盐液体培养基（MSM）中呈现s型生长，7d后对联苯菊酯的降解率达到87．9％。单因素试验表明，菌株最适降解条件为pH7．0、30oC，初始菌株D600am=1．0。【结论与意义】蜡状芽孢杆菌BF．3能够有效降解联苯菊酯，在环境中联苯菊酯残留的生物修复方面具有应用潜力。

Isolation, identification and degradation characteristics of a bifenthrin-degrading bacterial strain BF-3

[ Backgroud ] Bifenthrin is a synthetic organic compound similar to natural pyrethrins, and has been widely applied against agricultural pest during the last decades. Due to its relative stability and long residual life in the environment, its residues have be- come a serious problem in export fruits, vegetables and tea microbial degradation, due to its speed and environmental safety could be an effective way to deal with the pesticide residues. [ Method] The bacterial strain capable of degrading bifenthrin was isolated from sludge through the enriched culture. It was identified through its morphological, physiological and 16S rDNA sequence analysis. Its degradation characteristics was studied by using single factor tests. [ Result ] A bacterial strain BF-3, capable of degrading bifenthrin, was isolated. We identified and characterised a Gram-positive bacterial strain BF-3, belonging to Bacillus cereus genus. The strain showed S growth in minimum salts medium （MSM） containing 100 mg ~ L-1 bifenthrin, and after 7 days, the bifenthrin- degradation reached 87.9%. The single factor tests indicated that the optimal values for pH, temperature and initial inoculum densi- ty was pH 7.0, 30 ℃ and D600nm = 1.0, respectively. [ Conclusion and significance] The identified strain BF-3 could efficiently degradate bifenthrin, suggesting its great application potential to eliminate bifenthrin residues in the environment.