Two bacterial strains (BQ1 and BQ8) were isolated from decomposed soft foam. These were selected for their capacity to grow in a minimal medium (MM) supplemented with a commercial surface-coating polyurethane (PU) (Hydroform) as the carbon source (MM-PUh). Both bacterial strains were identified as Alicycliphilus sp. by comparative 16S rRNA gene sequence analysis. Growth in MM-PUh showed hyperbolic behavior, with BQ1 producing higher maximum growth (17.8 ؎ 0.6 mg ⅐ ml ؊1 ) than BQ8 (14.0 ؎ 0.6 mg ⅐ ml ؊1 ) after 100 h of culture. Nuclear magnetic resonance, Fourier transform infrared (IR) spectroscopy, and gas chromatographymass spectrometry analyses of Hydroform showed that it was a polyester PU type which also contained N-methylpyrrolidone (NMP) as an additive. Alicycliphilus sp. utilizes NMP during the first stage of growth and was able to use it as the sole carbon and nitrogen source, with calculated K s values of about 8 mg ⅐ ml ؊1 . Enzymatic activities related to PU degradation (esterase, protease, and urease activities) were tested by using differential media and activity assays in cell-free supernatants of bacterial cultures in MM-PUh. Induction of esterase activity in inoculated MM-PUh, but not that of protease or urease activities, was observed at 12 h of culture. Esterase activity reached its maximum at 18 h and was maintained at 50% of its maximal activity until the end of the analysis (120 h). The capacity of Alicycliphilus sp. to degrade PU was demonstrated by changes in the PU IR spectrum and by the numerous holes produced in solid PU observed by scanning electron microscopy after bacterial culture. Changes in the PU IR spectra indicate that an esterase activity is involved in PU degradation.Polyurethane (PU) was developed by Otto Bayer as a substitute for rubber at the beginning of World War II (1938). Due to its range of properties, the polymer is widely used, for example, in liquid coatings and paints, adhesives, sealants, flexible and rigid foams, and elastomers (7). Since PU is such a versatile polymer, PU production has increased, but this has brought with it the problem of safe disposal. Each year, more than 5 million tons of shredder residue containing different plastics and PU foams is generated in the United States and Canada (6). Several mechanical processes, such as regrinding, flexible foam bonding, adhesive pressing, and compression molding, as well as chemical techniques, such as glycolysis, hydrolysis, pyrolysis, and hydrogenation, are used for the recovery of the starting materials or in the production of other PU types (8). Recently, the development of new strategies based on the utilization of biopolymers such as poly[(R)-hydroxyalkanoic acids] (21), the enzymatic polymerization of polyesters and degradation of PU (28), and the discovery of microorganisms (fungi and bacteria) able to utilize PU as a source of carbon and nitrogen (12,31,32) is leading the move to a greener chemical industry.A number of bacterial strains, such as Corynebacterium sp., Pseudomonas fluorescens, P. ch...