BIODEGRADATION OF CROSS-LINKED ACRYLIC POLYMERS BY A WHITE-ROT FUNGUS

Two synthetic superabsorbent crosslinked acrylic polymers were mineral ized by the white-rot fungus Phanerochaete chrysosporium. The amount o f polymer converted to CO2 increased as the amount of polymer added to the cultures increased. In the presence of sufficiently large amounts of the superabsorbents, such that all of the culture fluid was absorb ed and a gelatinous matrix was formed, the fungus still grew and miner alization was observed. Neither the polymers, nor their degradation pr oducts were toxic to the fungus. While the rates of mineralization wer e low, all of the polymers incubated in the liquid fungal cultures wer e completely depolymerized to water soluble products within 15-18 days . The depolymerization of the polymers was observed only in nitrogen l imited cultures of the fungus which secrete the lignin degradation sys tem, however, the water soluble products of depolymerization were mine ralized in both nutrient limited and sufficient cultures of the fungus . The rate of mineralization of the depolymerized metabolites was more than two times greater in nutrient sufficient cultures. Following lon ger incubation periods, most (> 80 %) of the radioactivity was recover ed in the fungal mycelial mat suggesting that carbon of the polymer ha d been converted to fungal metabolites.