A thermophile, strain 23, assimilating poly(ethylene-co-vinyl alcohol) (EVOH) was isolated from soil using an enrichment culture at 60 degrees C. The strain grew on EVOH, decreased the solution viscosity of EVOH, and accumulated total organic carbon (TOC) in the medium. It was also capable of degrading poly(vinyl alcohol). The strain was identified as Bacillus stearothermophilus which has an optimum growth temperature around 58 degrees C.