Screening and Characterization of Benzo (a) pyrene Degrading Bacteria and Their Degradation Properties

Efficient microbial resource for degrading high-molecular-weight polycyclic aromatic hydrocarbons (PAHs), especially benzo(a)pyrene (BaP), is still lacking. This study screened and obtained four BaP-efficient degrading bacteria, H1 (Brucella anthropi), H2 (Bacillus cereus), M1 (Brucella anthropi) and M2 (Brucella anthropi), through enrichment culture, morphology observation, physiological and biochemical analysis and 16S rDNA gene sequence comparison. The degradation characteristics of the four strains under different temperatures and pH values were investigated. The results show that: (1) All the four strains could survive and maintain activity in an environment with pH of 5.5-8.5 and temperature of 25-37 ℃, and the optimal conditions for all were temperature of 30 ℃ and pH of 7.5; (2) Under the condition of T=30 ℃ and pH=7.0, after 5 days of degradation of BaP with an initial mass concentration of 5 mg·L^-1, the degradation rates of H1, H2, M1, and M2 reached 66.32%, 79.26%, 82.14% and 61.81%, respectively; (3) Brucella anthropi M1 showed especially excellent degradation ability for high-molecular-weight PAH BaP under the optimal degradation conditions and had good application potential in bioremediation. The research results provide valuable biological resources for bioremediation and technical support for the efficient bioremediation of BaP-polluted environments.