Biodegradation of a colloidal ester-based polyurethane by soil fungi

Four species of fungi were isolated from soil and found to degrade ester-based polyurethane in a polyurethane-agar clearing assay. One of these isolates, Curvularia senegalensis, secreted an extracellular enzyme-like factor with esterase properties, as determined by fluorescein diacetate hydrolysis, and this active factor was partially purified by ammonium sulfate fractionation. The polyurethane-clearing factor had an isoelectric point of 5·1 and a molecular weight of 28 kDa. It was stable to heating at 100°C for 10 min and was inhibited by phenylmethylsulfonyl fluoride.