Isolation of a fungal strain capable of degrading benzo [a] pyrene and its degradation characteristics
一株苯并[a]芘高效降解真菌的筛选与降解特性

A fungal strain, BF-1, with optimal degradation ability for the polyeyclic aromatic hydrocarbon (PAH) benzoa] pyrene (Ba] P) wasisolated from long-term PAH-contaminated soil. The strain was identified as Trichoderma viride. The effects of B a] P concentration, various heavy metalsand culture media on the degradation ability of the fungal strain were further studied using repeated subcultures in liquid medium with Ba] P as the onlycarbon source. The highest degradation rate of 5 mg·L~(-1) B a] P by BF~(-1) was 68.28 % after a 6-day culture at 32 ℃. After a 6-day oscillating culture at 32℃, the degradation rates of 10 and 25 mg·L~(-1) Ba] P in the culture medium were 73.29% and 87.36% , respectively. Addition of Cu~(2+) (50mg·L~(-1)) could appreciably inhibit the biedegradation of B a] P by BF- 1, and Pb~(2+) (300 mg· L~(-1)) and Cd~(2+) (100 mg·L~(-1)) also affected the rate ofdegradation, but the strain had strong tolerance to Pb~(2+) (300 mg· L~(-1)) or Cd~(2+) (100 mg·L-1). In particular, there was an obvious inhibitory effect ofZn2 + (200 mg· L~(-1) on the rate of degradation. After inoculation in potato dextrose broth culture media, BF- 1 could degrade 5 mg·L ~(-1)B a] P at a rateof 71.31% in 6 days, and compared with the results above, it was concluded that the culture media had minimal effect on the degradation of B a] P.Therefore, fungal strain BF-1 should he valuable in degrading Ba] P because it can tolerate a wide range of culture conditions.