Aerobic biodegradation of nonylphenol by cold-adapted bacteria

Three strains capable of mineralizing nonylphenol as sole carbon source were isolated from a sample of contaminated soil and characterized as two Pseudomonas spp. and a Stenotrophomonas sp. The two Pseudomonas spp. expressed characteristics typical of psychrophiles growing optimally of 10 degrees C and capable of growing at 0 degree C. The Stenotrophomonas sp. was more likely psychrotrophic because it had an optimal temperature between 14 and 22 degrees C although it was not capable of growing at 4 degrees C. At 14 degrees C, one of the Pseudomonas spp. exhibited the highest rate of degradation of nonylphenol (4.4 mg l-1 d-1), when compared with axenic or mixed cultures of the isolates. This study represents, to the best of our knowledge, the first reported case of cold-adapted microorganisms capable of mineralizing nonylphenol.