污染土壤中原位阿特拉津降解菌的分离和鉴定

为克服传统富集培养分离降解菌的局限性,直接将长期受阿特拉津污染的土壤稀释后,涂布于加有土壤浸出液和阿特拉津农药的平板,分别从两个采自不同地区的污染土壤中各分离了一株高效广谱降解菌AG1和ADG1：它们能以阿特拉津为唯一碳源、氮源和能源生长,能分别在44h和48 h内降解1 000mg L^-1的阿特拉津,降解率100%;它们还能以扑草净、西玛津等三嗪类除草剂为唯一氮源生长.16S rDNA核苷酸序列分析结果表明菌株AG1与ADG1都与节杆菌属（Arthrobacter）的细菌有高度同源性,结合两株菌的形态特征及生理生化特征,将它们鉴定为Arthrobacter spp..PCR扩增两株菌的降解基因,结果表明它们的降解基因都是trzN和atzBC的组合,这是国内首次报道具有该基因类型的阿特拉津降解菌.

ISOLATION AND IDENTIFICATION OF IN SITU ATRAZINE-DEGRADING BACTERIA FROM CONTAMINATED SOILS

To overcome limitations of the traditional enrichment culturing method for degrading bacteria isolation, two strains of bacteria, AG1 and ADG1, capable of degrading atrazine efficiently, were isolated by diluting and plating atrazine-contaminated soils directly onto plates coated with soil extracts and atrazine. They grew in medium with atrazine as the sole sources of nitrogen, carbon and energy, degrading 1 000 mgL^- 1 of atrazine within 44 h and 48 h, respectively, and could also grew with some other s-triazine herbicides as sole nitrogen sources. Based on their 16S rDNA sequences analysis and their physiologic and biochemical characteristics, AG1 and ADG1 were identified as Arthrobacter spp.. Results of amplifying their degrading genes with PCR, showed that atrazine metabolic genotype of AG1 and ADG1 were both combination of trzN and atzBC. It is the first report in the country about atrazine-degrading bacteria with such metabolic genotypes.