一株新的多菌灵高效降解茵的筛选与降解特性分析

从长期施用多菌灵农药的土壤中，通过富集筛选，获得1株新的多菌灵高效降解菌株。通过生理生化实验和16SrDNA序列同源性分析鉴定该菌株，应用高效液相色谱法对纯培养条件下菌株的降解特性和粗酶提取液的降解性能进行了分析。结果表明，筛选所获得的菌株与Raoultella菌属的亲缘关系最近，将其命名为Raoultellasp．MBC，该菌株能在以多菌灵为唯-碳源的无机盐培养基中生长；25℃、pH7．0、200r·min。的最适生长条件下避光振荡培养72h，多菌灵的降解率达到100％；在最适培养条件下外加氮源和碳源在培养后期均可以提高多菌灵的降解率，外加氮源对多菌灵的降解效果优于外加碳源；该菌体的粗酶提取液具有降解多菌灵活性，且多菌灵降解酶为诱导酶。研究结果为多菌灵污染土壤的生物修复和酶修复提供了材料和理论依据。

Identification and Characterization of a Newly Isolated Carbendazimdegrading Bacterial Strain MBC

A novel bacterial strain, which can effectively use carbendazim as sole carbon and energy source, was isolated from longterm carbendazim administered soil by enrichment screening. Based on the analysis of physiological and biochemical characteristics, 16S rDNA gene sequence homology and phylogenetic tree, the isolate was identified. Its degradation characteristics and degradation capability of the lysate were tested by HPLC. The new bacterial strain was identified as Raoultella sp. and named MBC. Results showed that this strain could utilize carbendazim as sole carbon source for growth, and could degrade 100% of carbendazim after 72 h shaking culture at 200 r· min^-1, 25 ~C and pH 7.0. Its degradation rate was increased by adding exogenous carbon and nitrogen source into the medium at the later stage of culture, and the degradation of adding exogenous nitrogen source was more effective than that of carbon source. The lysate had a degrading activity of carbendazim, and the catabolic enzymes were the induced enzyme. These results provided a rationale and a material for bioremediation of longterm carbendazimcontaminated soil.