[Degradation and kinetics of pyrene and benzo [a] pyrene by three bacteria in contaminated soil]

Degradation kinetics of pyrene and benzo [a] pyrene (BaP) in soil by three individual strains of bacteria were examined using the Michaelis-Menton and Monod dynamic models. There were significant differences occurred in the degradation rates of pyrene and BaP by the three individual strains. When the initial concentrations of pyrene or BaP was 50 mg/kg in soil, the degradation rates of pyrene by Bacillus sp. SB02, Zoogloea sp.SB09, and Flavobacterium sp.SB10 in 42 days were 42.69%, 32.88% and 25.07% respectively for pyrene. Similarly, degradation rates of BaP by Bacillus sp. SB02, Zoogloea sp. SB09, and Flavobacterium sp. SB10 in 42 days were 33.04%, 25.39% and 22.02% respectively for BaP. In addition, there also were significant differences occurred in the degradation rates per day of pyrene and BaP by the three individual strains. The most rapid degradation of pyrene and BaP by Bacillus sp. SB02 occurred in one week, and 20.88% of pyrene and 12.6% of BaP were degraded. However, Zoogloea sp. SB09 had a slower degradation, while Flavobacterium sp. SB10 had the slowest degradation.