氯氰菊酯降解菌株L12的分离鉴定及降解特性

摘要

[Objective]To isolate and characterize bacteria to degrade cypermethrin ( CP).[Methods]We used enrichment culture to isolate and characterize bacterial strains based on the observation of morphological and biochemical characters and analysis of 16S rRNA gene sequences.We determined the concentration of CP, metabolite, densities of strain cells and cell surface hydrophobicity ( CSH) in pure culture liquid.[Results]We isolated a bacterium able to effectively degrade CP from polluted wastes of pesticide plant and assigned it as strain L12.Phylogenetic analysis based on 16S rRNA gene showed the similarity of 99％ between strain L12 and Bacillus cereus.In pure culture with CP as the sole carbon and energy source, 85.6％ of CP at initial concentration of 50 mg /L was degraded in 5 days.Thin layer chromatography (TLC) analysis of the culture extracts revealed presence of a metabolite ( Rf0.13) , and HPLC analysis confirmed the retention time of the metabolite (2.26min) corresponded with 3-phenoxybenzoic acid (3-PBA) standard.The method of microorganism adhering to hydrocarbon (MATH) was used to analyze strain L12 of the highest CSH of 68.91％.[Conclusion]The results showed that strain L12 belonged to Bacillus cereus,which showed CSH and capacity to degrade CP to 3-PBA.%[目的]通过分离纯化氯氰菊酯降解菌,研究降解特性为实际应用提供理论依据.[方法]利用富集驯化培养技术分离菌株,通过形态、生理生化特征及16S rRNA基因序列分析鉴定菌株.测定培养液中氯氰菊酯的浓度和代谢产物以及菌体细胞的密度和细胞表面疏水性,研究菌株的降解特性.[结果]从生产氯氰菊酯的农药厂污水曝气池中,分离到1株能降解氯氰菊酯并以之为唯一碳源进行生长的细菌菌株L12.16SrRNA基因序列相似性比较表明,分离出的菌株与蜡状芽孢杆菌(Bacillus cereus)的相似性高达99%.以初始浓度为50 mg/L,的氯氰菊酯为唯一碳源时,5 d内菌株对氯氰菊酯的去除率为85.6%;薄层层析分析表明,在R,0.13处有代谢产物产生,经HPLC分析发现其与3.苯氧基苯甲酸(3-PBA)的保留时间一致(2.26min);采用微生物粘着碳烃化合物法(MATH)对该菌株的细菌表面疏水性进行测定,结果表明,菌株L12的细胞表面疏水性最高为68.91%.[结论]分离出的氯氰菊酯降解菌属于Bacillus cereus菌株,该菌株对氯氰菊酯具有较高的降解能力,同时产生代谢产物3-PBA,而且具有较高的细胞表面疏水性.