Effects of natural metabolic mixtures of PAHs on its biodegradation

The effects of metabolites of anthracene or phenanthrene on the biodegradation of anthracene or phenanthrene have been studied.The results showed that the natural state of metabolic mixtures of anthracene or phenanthrene exhibited promoting effects on biodegradation of anthracene or phenanthrene,the removing rates of anthracene were increased by 3.07%~6.10% within 156 h,and those of phenanthrene were 13.14%~30.35% within 60h.The biodegradation processes of anthracene or phenanthrene by Bacillus sp.CN2 could be described as first-order kinetics,and the only difference was that the values of k(the rate constant in the kinetic equation) for control groups were less than that of the degradation systems with addition of metabolic mixtures.The results also indicated that adding metabolic mixtures could enhance the biodegradation rate of anthracene and phenanthrene more obvious during earlier degradation stages than later stages,and for anthracene,the degradation rate increased by 0.281~1.20 mg/L·h within 2 h,and for phenanthrene,it was 0.570~1.13 mg/L·h.The metabolic mixtures could function as pH value buffer actions for the degradation fluids,so the pH values decreased slower than control groups.