咪唑乙烟酸降解菌S181的分离鉴定及其降解特性

Isolation and Identification of Imazethapyr Degradable Actinomyces S181 and Its Degradation Characteristics

为咪唑乙烟酸污染土壤的生物修复提供菌源,采用瓶富集培养法,从长期施用咪唑乙烟酸的土壤中筛选出1株对咪唑乙烟酸降解能力较强的放线菌,命名为S181.该菌株可利用咪唑乙烟酸为唯一氮源生长.经形态特征、生理生化特性及16S rRNA序列分析,初步鉴定该菌株为大宫链霉菌(Streptomyces omiyaensis).以S181菌体生长量和咪唑乙烟酸降解率为指标,研究了主要因素(温度、pH、初始浓度和接菌量)对S181生长和降解能力的影响.结果表明,菌株S181最佳生长和降解条件为30℃,pH为7.0,初始咪唑乙烟酸浓度为200 mg·L-1,接菌量3%.在此条件下,该菌株在去氮源高氏一号培养液中培养5 d,咪唑乙烟酸的降解率为84%.

A selection of actinomyces that could degrade imazethapyr was conducted to provide actinomyces source for bioremediation of soil contaminated by imazethapyr.A strain of actinomyces was isolated from the samples of soil where imazethapyr had been applied for a long-term by use of bottle enriched culture and named S181.The strain had strong ability to degrade imazethapyr and could grow using mazethapyr as the sole nitrogen.The strain was related and shared characteristics to genus Streptomyces omiyaensis according to the physiological and biochemical properties as well as 16S rRNA sequence analysis.The influencing factors（temperature,pH,concentration and inoculum） were studied with fungus growth mass and degradation ratio as indexes.The results showed that the optimal degradation ratio occurred at the condition of inoculation ratio of 3%,200 mg·L-1 imazethapyr,at 30℃ and pH 7.0.Under these conditions,84% imazethapyr had been degraded by S181 in medium Gao 1 without nitrogen after 5 days.