The biodegradation of poly(butylene succinate) (PBS) was studied under controlled composting conditions. The ultimate biodegradation percentage revealed that the powder-formed sample showing the best biodegradability may be ascribed to the largest specific surface. The biodegradation process of PBS under controlled composting conditions exhibited three phases. The biodegradation in the first phase was slow, got accelerated in the second phase, and showed a leveling-off in the third phase. The degradation of PBS film after composting was further characterized by gel permeation chromatography (GPC) and scanning electron microscopy (SEM). Four strains were isolated from the compost and identified as Aspergillus versicolor, Penicillium, Bacillus, and Thermopolyspora. Their degrading abilities to PBS powder in liquid medium were different. Among them, Aspergillus versicolor was the best PBS-degrading microorganism. (c) 2005 Wiley Periodicals, Inc.