溴苯腈降解菌株Pseudomonas sp.BX-1的分离鉴定及降解特性研究

Isolation of Bromoxynil-Degrading Bacterium Pseudomonas sp.BX- 1 and Its Degradability

为解决溴苯腈残留问题,采用连续富集传代培养的方法,从长期生产溴苯腈的农药厂污染土壤中分离筛选到1株溴苯腈降解菌株BX-1。经过形态学特征、生理生化特征和16S rRNA基因序列系统发育分析,将菌株BX-1鉴定为假单胞菌属(Pseudomonas)。菌株BX-1能以溴苯腈为唯一碳源生长,能在40h内将50 mg·L-1的溴苯腈完全降解,其降解溴苯腈的最适温度为30℃,最适p H值为7.5。0.1m M Fe2+能轻微地促进菌株BX-1降解溴苯腈,而Hg2+能强烈抑制该降解过程。此外,菌株BX-1对溴苯腈的降解效果与起始接种量呈正相关。借助MS/MS鉴定出菌株BX-1降解溴苯腈的中间代谢产物为3,5-二溴-4-羟基苯甲酸和2,6-二溴苯酚。该研究结果为全面阐释溴苯腈的微生物降解机制和溴苯腈污染土壤的生物修复提供了新的种质资源。

In order to solve the bromoxynil residue,a bromoxynil-degrading strain, named BX-1, was isolated from bromoxynil-contaminated soil of bromoxynil factory by the conventional enrichment culture technique. Based on the morphological characteristics, physiological and biochemical characteristics, and phylogenetic analysis of 16S rRNA gene sequence, the strain BX-1 was identified as Pseudomonas sp. Strain BX-1 could completely degrade 50 mg·L^-1 bromoxynil in 40 h and live on bromoxynil as sole carbon source. The optimum temperature and pH for bromoxynil degradation by strain BX-1 were 30℃ and 7.5, respectively. The bromoxynil degradation activity of strain BX-1 were strongly inhibited by 0.1 mM of Hg^2＋, but slightly enhanced by 0.1 mM of Fe^2＋. With the increase of inoculation, the degradation rate of bromoxynil by strain BX-1 also accelerates. Based on MS/MS analysis, the intermediate metabolite of bromoxynil degraded by strain BX-1 were identified as 3,5-dibromo-4-hydroxybenzoic acid and 2,6-dibromophenol. This study provided new microbial resources for illumination of bromoxynil-degrading mechanism comprehensively and bioremediation of contaminated soil by bromoxynil.