Pyrene degradation and detoxification in soil by a consortium of basidiomycetes isolated from compost: role of laccases and peroxidases.

A consortium of three basidiomycetes isolated from compost was investigated for pyrene degradation in soil microcosms. Pyrene concentration, glucose and ammonium evolution, moisture content, ligninolytic enzyme activities and phytotoxicity (germination index) on Lepidium sativum L. seeds were monitored. The fungal consortium grown on straw was found able to efficiently colonize soil and remove about 56 out of 100 mg kg(-1) of soil dry weight of pyrene in 28 days; in the meantime the germination index increased indicating a reduction of phytotoxicity. A glucose supply after 2 weeks was found useful to ensure fungal growth and activity; maintenance of moisture content below 70% allowed a good aeration of the system and improved degradation rates. Enzymatic assays showed that laccase and manganese independent peroxidase activity could have played a role in the degradation process.