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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。
To solve the problem of bromoxynil residues, a strain of bromoxynil-degrading strain BX-1 was isolated and screened from the contaminated soil of long-term production of bromoxynil by continuous enrichment subculturing. Strain BX-1 was identified as Pseudomonas by morphological, physiological and biochemical characteristics and phylogenetic analysis of 16S rRNA gene sequences. Strain BX-1 was able to grow with bromoxynil as the sole carbon source. It could completely degrade 50 mg · L-1 of bromoxynil within 40h. The optimum temperature for bromoxynil degradation was 30 ℃. The optimal pH The value of 7.5.0.1 M Fe2 + can slightly promote the degradation of bromoxynil in strain BX-1, whereas Hg2 + strongly inhibits the degradation. In addition, the degradation of bromoxynil by strain BX-1 was positively correlated with the initial inoculum size. The intermediate metabolites of strain BX-1 for the degradation of bromoxynil were identified as 3,5-dibromo-4-hydroxybenzoic acid and 2,6-dibromophenol by MS / MS. The results provide a new germplasm resource for comprehensively explaining the microbial degradation mechanism of bromoxynil and the bioremediation of bromoxynil-contaminated soil.