阿特拉津降解菌株的分离、鉴定和工业废水生物处理试验

用液体无机盐培养基富集培养法和无机盐平板直接分离法, 从生产阿特拉津的农药厂的废水和污泥混合物中分离到13个能以阿特拉津为唯一氮源生长的细菌菌株。通过16S rRNA基因序列分析, 11个菌株被鉴定为Arthrobacter spp., 2个菌株被鉴定为Pseudomonas spp.。对阿特拉津降解活力最高的Arthrobacter sp. AD30和Pseudomonas sp. AD39的降解基因组成和降解特性进行了详细研究。降解基因的PCR扩增表明, AD30和AD39都含有trzN-atzBC基因, 能将有毒的阿特拉津降解成无毒的氰尿酸。降解实验表明, 向阿特拉津浓度为200 mg/L的无机盐培养基中分别接种等量的AD30、AD39和这两个菌株的混合菌液, 30°C振荡培养48 h以后, 阿特拉津去除率分别为92.5%、97.9%和99.6%, 表明混合菌的降解效果好于单菌。用AD30和AD39的混合菌液接种阿特拉津浓度为176 mg/L的工业废水, 30°C振荡培养72 h以后, 99.1%的阿特拉津被去除, 表明混合菌株在阿特拉津工业废水的生物处理中有很好的应用潜力。

Isolation and Characterization of Atrazine-degrading Strains and Biotreatment Experiment of Industrial Wastewater

By using enrichment culture in liquid minimal medium or direct culture on minimal medium plates, thirteen bacterial strains (AD27-AD39) capable of utilizing atrazine as a sole nitrogen source for growth were isolated from a mixture of industrial wastewater and sludge from an atrazine manufacturing plant. Based on 16S rRNA gene sequencing, eleven strains were identified as Arthrobacter spp. and two strans were identified as Pseudomonas spp.. We further studied in detail the composition of atrazine-degrading genes and degradation characteristics of Arthrobacter sp. AD30 and Pseudomonas sp. AD39 that have high degradative activity. From PCR assays, it was indicated that both AD30 and AD39 strains contained atrazine-degrading genes trzN and atzBC and was capable of degrading toxic atrazine to nontoxic cyanuric acid. The biodegradation experiments showed that the percentage of atrazine removal were 92.5%, 97.9% and 99.6% respectively after AD30, AD39 or the mixture of the two strains were inoculated and incubated at 30°C for 48 hours in minimal media containing 200 mg/L atrazine, indicating that atrazine degradation by the mixed bacteria was more effective than the single strain. In addition, after industrial wastewater containing 176 mg/L atrazine was inoculated with the mixed bacteria and incubated at 30°C with shaking for 72 hours atrazine were removed by 99.1%, implicating that the mixed bacteria are good candidate for biotreatment of atrazine-containing industrial wastewater.