嗜铁细菌CAS17的分离鉴定及其对毒死蜱的降解特性研究

Isolation, identification and chlorpyrifos-degradation characteristics of siderophore producing bacterial strain CAS17

采用改良定向培育法，从获得的几株嗜铁细菌菌株中经过驯化筛选，获得1株对毒死蜱有较高降解作用的细菌CAS17.结合其生理生化特性及16S rRNA 序列分析，将其鉴定为耐盐短杆菌（Brevibacterium halotolerans）.生长特性和毒死蜱降解试验结果表明，该菌株对毒死蜱有较高的耐受性，在毒死蜱浓度达到800 mg·L^-1时仍可生长.最适毒死蜱降解浓度为≤100 mg·L^-1，降解率可达67%左右，浓度继续升高时降解效果明显降低；最适降解温度为30 ℃，对高温敏感；对pH值有着较强的适应范围，pH值在5-9之间的降解率波动不大；最适降解时间为48 h，振荡速率为150 r·min^-1，接种量为4%；适合其降解的最佳外加碳源为葡萄糖，最佳氮源为酵母粉，最佳无机盐为CaCl2.

The siderophore producing strain CAS17, capable of utilizing and degrading chlorpyrifos, was obtained and preliminarily identified as Brevibacterium halotolerans according to its physiological-biochemical characteristics and 16S rRNA sequence analysis. The growth and degradation characteristics of the strain were tested. The result showed that the strain could grow well when chlorpyrifos concentration was 800 mg·L^-1, indicating high tolerance to the high concentration of chlorpyrifos. For growth and chlorpyrifos degradation, the optimal conditions were concentration of no more than 100 mg·L^-1 with about 67% of the degradation rate, temperature of 30 ℃ pH value from 5 to 9, the fermentation parameters at 150 r·min^-1 for 48 h and inoculation quantity of 4%. The optimal additional carbon, nitrogen source and inorganic salt for chlorpyrifos degradation were glucose, yeast and CaCl2, respectively.