氯氰菊酯降解菌的筛选鉴定及其降解特性研究

Isolation and Identification of a Strain of Cypermethrin-Degrading Bacteria LQ-3 and Its Degradation Characteristics

从农药厂废水排放13附近的污泥中分离到1株能降解氯氰菊酯的细菌LQ-3。根据其形态、生理生化特征和16SrDNA（GenBank Accession No．FJ222585）序列分析，将该菌株鉴定为Starkeyasp．。LQ-3菌株只能以共代谢方式降解氯氰菊酯，在有酵母粉、蛋白胨、葡萄糖等营养物质存在的条件下，5d内对20mg·L^-1氯氰菊酯的降解率达到72．1％。LQ-3菌株降解氯氰菊酯的最适温度为30℃左右，pH值为7～8。LQ-3菌株还能降解功夫菊酯、甲氰菊酯、联苯菊酯和溴氰菊酯。酶的定域试验表明，LQ-3菌株降解氯氰菊酯的酶属于胞外酶。

A strain of cypermethrin-degrading bacteria referred to as LQ-3 was isolated from sludge collected from a wastewater outlet of a pesticide plant. Based on morphological, physiological and biochemical characteristics and 16S rDNA sequences analysis （GenBank Accession No. FJ222585） , LQ-3 was identified as Starkeya sp.. LQ-3 degraded cypermethrin through co-metabolism. When fed with nutrient substances, such as yeast extract, peptone and glucose, LQ-3 could degrade 72.1% of cypermethrin in the medium （20 mg . L^-1 ） in 5 d. The optimal pH and temperature for the degradation by LQ-3 was 7-8 and 30 ℃ , respectively. Strain LQ-3 was also able to degrade other pyrethroids such as cyhalothrin, fenpropathrin, bifenthrin and dehamethrin besides cypermethrin. The enzyme distribution experiment showed that the enzyme responsible for the cypermethrin degradation was extraeellular.