节杆菌AD26的分离鉴定及其与假单胞菌ADP对阿特拉津的联合降解

用富集培养法,从农药厂的工业废水中分离到高效降解除草剂阿特拉津的AD26菌株,通过16SrRNA基因序列分析,该菌株被鉴定为节杆菌（Arthrobacter sp.）。降解基因的PCR分析表明,AD26含有阿特拉津降解基因trzN和atzBC,它能以阿特拉津为唯一氮源、蔗糖或柠檬酸钠为碳源生长,将阿特拉津降解成氰尿酸,降解速度快但降解不完全。假单胞菌（Pseudomonas sp.）ADP是Wackett实验室分离的阿特拉津降解菌株,含有阿特拉津降解基因atzABCDEF,能以阿特拉津为唯一氮源、柠檬酸钠为碳源（不能以蔗糖为碳源）生长,将阿特拉津降解成NH3和CO2,降解完全但降解速度慢。在阿特拉津浓度为200mg·L^-1的无机盐培养基中进行的AD26和ADP混合培养表明,它们对阿特拉津的降解发生了互补和增强作用,两个菌株能在以阿特拉津为唯一氮源、蔗糖为碳源的培养基中生长,而且生长和降解速率都好于单个菌株,培养72h后阿特拉津去除率达到99.9%,其中76.7%的阿特拉津被降解成NH3和CO2。这表明由节杆菌AD26和假单胞菌ADP组成的混合菌株在阿特拉津废水处理和污染土壤的生物修复中有很好的应用潜力。

Isolation and Identification of Arthrobacter sp. AD26 and Joint Degradation of Atrazine by Arthrobacter sp. AD26 and Pseudomonas sp. ADP

A highly efficient atrazine-degrading bacterium, strain AD26, was isolated from an industrial wastewater sample using enrichment culture. 16S rRNA gene sequencing identified AD26 as an Arthrobaeter sp. strain. PCR assays for degradation genes indicated that AD26 contains atrazine-degrading genes trzN and atzBC. This strain uses atrazine as sole source of nitrogen and sucrose or sodium citrate as the carbon source for growth and degrades atrazine to cyanurie acid. Although AD26 exhibited a higher degradation rate, the degradation of atrazine was not complete. Pseudomonas sp. strain ADP is an atrazine-degrading strain isolated by Wackett and his cooperators. This strain contains atrazine-degrading genes atzA BCDEF, uses atrazine as sole source of nitrogen and sodium citrate （not sucrose ）as the carbon source for growth and degrades atrazine to NH3 and CO2. Although atrazine degradation of ADP was complete, the degradation rate of atrazine was slower. Co-cultivation of AD26 and ADP in minimal medium containing 200 mg·L^-1 of atrazine showed that they exhibited joint degradation of atrazine and higher degradative rate. The two strains could grow quickly in the minimal medium that atrazine as sole source of nitrogen and sucrose as carbon source. They were capable of removing atrazine in the medium at 99.9% in 72 h, and 76.7% of atrazine was degraded to NH3 and CO2. These results indicated that co-cultivation ofArthrobaeter sp. strain AD26 and Pseudomonas sp. strain ADP has great application potentialities in bioremediation of atrazine-contaminated soils and waters.