真菌对污染水稻土中苯并[a]芘共代谢降解研究

在恒温和恒定转速培养条件下，模拟生物泥浆反应器法，选择从石油污染土壤中分离出来的青霉菌、黑曲霉、白腐真菌等3种真菌，在添加不同浓度菲和邻苯二甲酸作为共存底物情况下，研究其对水稻土中苯并a]芘（Ba]P）的共代谢降解。结果表明，未灭菌土壤对Ba]P有降解能力。当土壤中添加菲时，提高了Ba]P在土壤中的降解率，100 mg kg-1浓度菲处理的降解率显著高于200 mg kg-1浓度菲处理，邻苯二甲酸对Ba]P降解影响不大。灭菌土壤中的Ba]P几乎没有降解。添加菲及邻苯二甲酸均促进了青霉菌对Ba]P的降解，其中菲浓度为100 mg kg-1处理效果最显著。与灭菌土壤相比，接种黑曲霉提高了Ba]P的降解率，但添加菲与邻苯二甲酸却均抑制了黑曲霉菌对Ba]P的降解。白腐真菌能有效地降解Ba]P，但高浓度菲抑制了白腐真菌对Ba]P的降解，同时邻苯二甲酸对促进白腐真菌降解Ba]P的效果不明显。

EFFECTS OF FUNGI ON CO-METABOLIC DEGRADATION OF BENZO[A]PYRENE IN PADDY SOIL

Simulated bioslurry remediation of PAHs contaminated soil was carried out. Three strains of fungi isolated from petroleum-contaminated soils were inoculated into paddy soils different in application rate of phenanthrene and phthalic acid, to investigate their effects of co-metabolic degradation of Ba]P therein. Results show that in natural soils, some native microorganisms were able to degrade Ba]P and addition of low molecular weight PAHs-phenanthrene increased, degradation rate of Ba]P in the soil. The effect was greater when the application rate of phenanthrene was 100 mg kg-1 than when it was 200 mg kg-1. But the addition of phthalic acid did not show much effect. In sterilized soils, degradation of Ba]P in soils was hardly observed. However, inoculation of Penicillium stimulated degradation of Ba]P in all the three treatments, i.e. phenanthrene at 100 mg kg-1, phenanthrene at 200 mg kg- and phthalic acid, but only in the treatment of phenanthrene at 100 mg kg-1 the effect was significant. Inoculation of Aspergillus niger also showed similar effect, which, however, was inhibited by the presence of phenanthrene and phthalic acid in the soil. White-rot fungus could effectively degrade Ba]P, but high concentration of phenanthrene inhibited its effect in the soils, and phthalic acid was neither an optimal co- substrates of white-rot fungus in degrading Ba]P in paddy soils.