赤子爱胜蚓肠道中苯并[a]芘降解菌BJ-1的分离鉴定及其降解能力的测定

Isolation and Identification of Benzo[a]Pyrene-degrading Strain BJ-1 and Determination of its Degrading Capability in the Gut of Eisenia fetida

苯并[a]芘是环境中广泛分布的持久性有机污染物,利用赤子爱胜蚓(Eisenia fetida)肠道中的微生物有效降解苯并[a]芘,是当前对环境中苯并[a]芘污染进行生物修复的新途径。本研究以苯并[a]芘(8 mg·L-1)作为唯一碳源对赤子爱胜蚓肠道微生物进行胁迫培养5代,使用平板稀释涂布法分离筛选出1株苯并[a]芘高效降解菌株BJ-1,通过形态学观察、生理生化试验以及16S r RNA基因测序分析确定其分类地位,并采用高效液相色谱法(HPLC)检测菌株BJ-1对苯并[a]芘的降解能力。结果显示:菌株BJ-1鉴定为施氏假单胞菌(Pseudomonas stutzeri),且在30℃,无机盐培养基中苯并[a]芘质量浓度为8 mg·L-1的条件下,胁迫培养28 d后,菌液0D600 nm值增长至0.424,菌株降解率可达86.01%。研究表明:赤子爱胜蚓肠道中能筛选出有效降解苯并[a]芘的微生物,丰富了降解有机污染物苯并[a]芘的微生物资源,从而为环境中苯并[a]芘污染的生物修复提供了新思路。

Benzo[a]pyrene（Ba P） is a widely distributed persistent organic pollutant in the environment. Isolating microbia from the gut of earthworm Eisenia fetida is a new bioremediation technique for degradation of Ba P. A strain（BJ-1）was isolated from the gut of earthworm through spread plate after 8 mg·L-1 Ba P stress culture. This strain was identified by the methods of morphologic observation, physiological and biochemical experiments as well as 16 S r RNA gene sequence analysis. The Ba P degradation ability of BJ-1 was tested by using high performance liquid chromatography（HPLC）. The results showed that the strain BJ-1 was a Gram-negative bacterium, which belonged to Pseudomonas stutzeri. After being cultured in Ba P（8 mg·L-1）as the sole carbon source for 28 days at30 ℃, the BJ-1 degraded Ba P at a rate of 86.01% and a density of 0.424（OD600 nm）. The results indicated that the Ba P-degrading strain could be isolated from the gut of earthworm, enriching the microbial resources for degrading Ba P. It provides a newviewfor the bioremediation of Ba P in the environment.