The yeast strain, Cryptococcus flavus GB-1, isolated from rice husks as a candidate producer of a biodegradable plastic (BP)-degrading enzyme. The genomic DNA sequence encoding the BP-degrading enzyme of GB-1 was determined. The enzyme was named CfCLE because the deduced amino acid sequence (239 amino acids) was found to be 93% identical to that of CLE of Cryptococcus sp. S-2 (accession No. BAK82405.1). The strain GB-1 forms a clear zone (halo) around its colonies on emulsified polybutylene succinate-co-adipate (PBSA) agar plates containing soybean oil but not on plates containing glucose. A UV-induced mutant from this strain, designated as GB-1-DMC1, formed halos on emulsified PBSA plates containing glucose and showed 1.53 U/ml of PBSA-degrading activity in liquid culture with glucose, which was more than 2.5-fold higher than that of the parent strain GB-1 (0.58 U/ml). Moreover, using xylose as a carbon source enhanced the PBSA-degrading activity of both strains. Xylose fed-batch cultivation of GB-1 and GB-1-DMC1 using a 5-1 jar fermentor for 72 h produced 12.1 and 21.2 U/ml of CfCLE, respectively. Purified CfCLE has a molecular mass of 22 kDa, and its optimal pH and temperature for enzyme activity is 7.8 and 45 degrees C, respectively. CfCLE degraded various BP cast films. (C) 2015 Elsevier Ltd. All rights reserved.