阿特拉津降解菌T3 AB1的分离鉴定及土壤修复

Isolation,identification and soil remediation of atrazine-degrading strain T_3 AB_1

【目的】从阿特拉津污染土壤分离高效降解菌株,进行分类学鉴定、降解特性及黑土修复能力初步研究,为阿特拉津污染土壤微生物修复提供新的菌株。【方法】通过形态特征、生理生化特征和16S rDNA序列分析方法进行菌株鉴定;通过培养时间、温度、pH值等环境因素的研究得出菌株的最佳降解条件;通过降解菌株接种于不同种类除草剂为唯一碳氮源培养基获得该菌株的降解谱;通过土壤接种和敏感作物盆栽生测试验验证菌株对阿特拉津污染土壤修复能力。【结果】本试验从黑龙江省讷河市长期施用阿特拉津的玉米田地中分离出一株能以阿特拉津为唯一碳氮源生长的细菌T3AB1,初步鉴定为节杆菌属(Arthrobacter sp.),该菌株在72 h内对500 mg/L阿特拉津(pH 8.0)的降解率高达99%,其降解能力较高的条件为pH7.0-8.0、25-30℃、摇培72-108 h,该菌株能够利用甲氧咪草烟、咪唑乙烟酸、氟磺胺草醚、氟乐灵、异噁草松为唯一碳氮源进行生长,处理168 h的降解率能够达到12.66%-40.54%,该菌株处理21 d能够显著恢复敏感作物水稻的各项生物量指标,且随着处理时间的延长,其对土壤的修复作用也会逐渐增强。【结论】从黑龙江省污染土壤中筛选得到的高效降解阿特拉津的节杆菌属近缘种T3AB1,土壤接种实验表明该菌株具有很好的土壤修复作用,可为阿特拉津生物修复的研究提供适宜菌种资源。

[Objective]To provide new atrazine-degrading strains for atrazine-polluted soil,we isolated the high-efficiency degradation bacterium from contaminated soil,identified with taxonomy,and studied the degrading characteristics and remediation capability of the strain in black soil.[Methods]We used morphological,physiological and biochemical characteristics and 16S rDNA sequences analysis to identify the strain.We studied the effect of environmental factors such as incubation time,temperature and pH on the strain growth and atrazine degradation to confirm the optimum degradation conditions.The strain＇s degradation range was studied by using different herbicides as sole carbon and nitrogen source.The strain＇s remediation capability to atrazine-polluted soil was tested by sensitive crop bioassay after inoculating in pot soil.[Results]We isolated a high-efficiency degradation strain T3AB1 that used atrazine as sole carbon and nitrogen source from maize field suffering atrazine in Nehe,Heilongjiang province.It was initially identified as a member of the genus Arthrobacter sp..The strain could degrade more than 99% of 500 mg /L atrazine（pH8.0） within 72 h.We determined the best degradation conditions as follows： pH7.0-8.0,25-30℃,72-108 h.In addition,the strain used other herbicides as sole carbon and nitrogen source such as imazamox,imazethapyr,trifluralinm,clomazone and fomesafen,and the degradation rate reached 12.66%-40.54% after 168 h.The strain could significantly remedy the sensitive rice crop biomass indexes after treating 21 days,and as time extending,its role in the remediation gradually increased.[Conclusion]The screened atrazine-degrading strain T3AB1 could be a suitable candidate for bioremediation of atrazine-polluted soil.