A process for using a common fungus found on the bark of trees to degrade pesticide wastes has been developed by UC Davis toxicologists. A strain of the white rot fungus known as Phanerochaete chrysosporium is used to break down the target chemicals. "This microorganism degrades many types of chemicals and has a proven ability to compete against other organisms," says Fumio Matsumura, a professor of environmental toxicology and associate director of the Toxic Substances Research and Teaching Program. In its natural environment, the fungus excretes an enzyme capable of digesting the tree bark's lignin, a substance that is very resistant to degradation. Matsumura and colleagues capitalized on this degradative ability of the fungus for use in breaking down pesticide residues in the soil. The contaminated soil could be placed in a bioreactor with the white rot fungus, which would bind with the pesticides. Since the fungus is an aerobic microorganism, it tends to rise to the surface of a solution in search of air. At the surface, the fungus exposes the targeted chemicals to ultraviolet light, hastening the degradation process. An article on this process for treating contaminated soils with a strain of white rot fungus was published in the July issue of the journal Environmental Science and Technology. The University of California has filed for a patent on the process. Matsumura will discuss the work Thursday, Aug. 29, during a talk titled "Biotechnological Approaches to Pesticide Waste Destruction Using White Rot Fungi" in the Agrochemicals Division.