Biodegradation of Poly(.EPSILON.-Caprolactone) Film in the Presence of Lysinibacillus sp. 70038 and Characterization of the Degraded Film

Poly (epsilon-caprolactone) (PCL) is one of the commercial biodegradable plastics and biocompatible polyesters that can be assimilated by microorganisms. Lysinibacillus sp. 70038 which degrades PCL film was screened from stock cultures by cultivation using an enrichment culture medium containing PCL film with the weight-averaged molecular weight (Mw) of 160,000 as a sole carbon source. Lysinibacillus sp. 70038 degraded 9.0% of PCL at 30 degrees C, 100 rpm, after 30 d. Scanning electron microphotograph (SEM) analysis of the degraded PCL film showed nearly 4 /i m of surface erosion, and the molecular weight distribution of the surface area of PCL film became broad and a low molecular weight polymer (Mn=6,900) was confirmed by gel permeation chromatography (GPC) after cultivation.