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

Key words: 
• Eisena fetida /
• Benzo[a]pyrene /
• micro-biological degradation /
• Pseudomonas

Abstract: 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（OD_{600 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.