DEVELOPMENT OF A PRACTICAL METHOD FOR INDUCING WHITE-ROT FUNGI TO GROW INTO AND DEGRADE ORGANOPOLLUTANTS IN SOIL

White-rot fungi degrade many hazardous organic compounds that are not readily degraded by other microorganisms. Some of these compounds are soil contaminants, so methods for using these fungi to decontaminate s oil through either land farming or composting technologies are being d eveloped. White-rot fungi normally colonize plants or plant residues ( e.g., wood) and do not grow well in unamended soil, particularly if it is not sterilized. A practical method to promote their growth in soil , without the use of large quantities of amendments or inoculum, is pr esented. A variety of assays' showed that growth of white-rot fungi in steamed soil is limited by availability of carbon and nitrogen source s, but not other nutrients. Ground alfalfa straw was a more effective inexpensive source of these nutrients than the other amendments that w ere tested. However, the fungi only sometimes colonized alfalfa-amende d nonsterile soil, as a result of competition from other microorganism s. Consistently high growth of the white-rot fungi in alfalfa-amended soil could be induced by adjusting the moisture content, adding the fu ngicide benomyl, and inoculating with benomyl-resistant fungi. In soil so treated, degradation (mineralization) of pentachlorophenol was muc h more rapid than in untreated soil.