DEGRADATION OF ATRAZINE BY THE LIGNOCELLULOLYTIC FUNGUS PLEUROTUS-PULMONARIUS DURING SOLID-STATE FERMENTATION

The biotransformation of atrazine added to a mixture of cotton and whe at straw (CWS) and inoculated with the white-rot fungus, Pleurotus pul monarius, was studied, as a proposed system for bioremediation. The co ncentration of methanol-extractable atrazine was reduced, due to both biological transformation and physical-chemical adsorption to the stra w. Only 32% of the total radioactivity added as C-14-ring-labeled atra zine to pasteurized CWS inoculated with Pleurotus was extracted two we eks after fungal colonization, and less than 70% from non-inoculated C WS. The reduction in extractable radioactivity increased with time of incubation. No mineralization of the triazine ring was found during si x weeks of incubation, but transformation to two groups of atrazine me tabolites, chlorinated and dechlorinated, occurred as a result of the activity of the fungus inoculated and natural bacterial population. Un extractable radioactivity was recovered after digesting the colonized substrate with H2SO4, indicating adsorption of the herbicide and its m etabolites to the straw. The results suggest that this process can be used to detoxify atrazine by both adsorption and biodegradation. Copyr ight (C) 1996 Elsevier Science Ltd.