[Effects of fungi on co-metabolic degradation of benzo [a] pyrene in droughty red soil].

Simulated bioslurry remediation of PAHs contaminated soil was carried out. Penicillium, Aspergillus niger and white-rot fungus etc. three strains of fungi isolated from petroleum-contaminated soils were inoculated into droughty red soils differently in application rates of phenanthrene and phthalic acid, to investigate their effects of co-metabolic degradation of B[a]P. Results show that in natural soils, some native microorganisms were able to degrade B[a] P and with addition of low molecular weight PAHs-phenanthrene increased degradation rate of B[a] P in the soil. The effect was greater when the application rate of phenanthrene was 100 mg x kg(-1) than 200 mg x kg(-1). But the addition of phthalic acid did not show much effect. In sterilized soils, degradation of B[a]P in soils was hardly observed, and application of co-metabolism has no significant effect. However, inoculation of Penicillium stimulated degradation of B[a]P in all three treatments, i.e., phenanthrene at 100 mg x kg(-1), phenanthrene at 200 mg x kg(-1) and phthalic acid, but the effect of phenanthrene treatment was better than that of phthalic acid treatment. Inoculation of Aspergillus niger also showed similar effect, however, was inhibited by the presence of phenanthrene and phthalic acid in the soil. The degradation ability of white-rot fungus to B[a]P was very poor, but both kinds of phenanthrene concentration and phthalic acid treatments all could promote white-rot fungus to degrade B[a]P in soils, and the effect of phenanthrene was better than that of phthalic acid.