一株高效降解氯氰菊酯细菌的分离鉴定及降解特性

Biodegradation of Cypermethrin by a Newly Bacterial Isolate, Kurthia sp. LF-1

筛选分离氯氰菊酯(cypermethrin)高效降解细菌,研究其降解特性。根据分离菌株的生理生化特征以及16SrDNA序列同源性分析鉴定降解菌;气相色谱法测定该菌降解氯氰菊酯的能力;利用化学消除剂消除细菌质粒,测定消除质粒后细菌降解能力,初步定位降解酶基因。从长期使用氯氰菊酯的土壤中筛选分离出三株优势菌,编号为LF-1、LF-2和LF-3。选择对氯氰菊酯降解潜力最高的菌株LF-1进行鉴定和降解特性研究。LF-1初步鉴定为kurthiasp.,该菌降解氯氰菊酯最适pH和温度分别为7、35℃;在最佳降解条件下培养8天,对100mg/L氯氰菊酯降解率达80.15%,LF-1还能降解甲氰菊酯、联苯菊酯等菊酯类农药。经SDS或EB消除质粒后,LF-1降解氯氰菊酯的能力丧失,表明该菌降解基因可能位于质粒DNA。LF-1能有效的降解多种菊酯类农药,该研究为菊酯类农药的生物修复提供理论依据。

Isolate, identify and assess the potential for the biodegradation of cypermethrin by bacteria from soil. The bacteria was screened by enrichment culture and identified based on biochemical characters, homology analysis of 16S rDNA sequence. The degrading characteristics of this strain were evaluated. The degrading potential was tested by plasmid cured strain for fixing position of degradation gene. Three predominant bacteria were obtained, and named as LF-1, LF-2 and LF-3. Of these, the LF-1 was selected for further study for biggest potential of cypermethrin degradation. LF-1 was identified as kurthia sp. The cypermethrin quantity was analyzed accurately by GC with μECD. The results showed 35 ℃, pH 7 were the optimum degradation conditions, respectively. LF- 1 could degrade cypermethrin up to 80.15% in a concentration of 100 mg/L within 8 d, and also degrade fenpropathrin, bifenthrin effectively. The plasmid cured strain could not degrade cypermethrin, which indicated that the degradation gene was probably involved in plasmid. The strain could degrade several synthetic pyrethroids and degradation characteristics showed the potential to be used in a bioremediation application in agriculture.