A thermotolerant Aspergillus sp. strain ST-01 degrading poly(epsilon-caprolactone) films was isolated. The polyester was degraded and assimilated giving 36 mg of cell from 100 mg sample and 10 mg yeast extract after 6 days at 50 degrees C. The degradation products were identified as succinic acid, butyric acid, valeric acid, and caproic acid. The isolate also degraded more than 90% film samples of polyhydroxybutyrate (PHB) and poly(tetramethylene succinate-co-tetramethylene adipate) at 50 degrees C.