ISOLATION, CHARACTERIZATION, AND SUBSTRATE UTILIZATION OF A QUINOLINE-DEGRADING BACTERIUM

A Gram (+) rod-shaped organism identified as a Rhodococcus sp. capable of growth utilizing quinoline as the dominant carbon, energy, and nit rogen source was isolated from soil. The isolate, designated as Rhodoc occus sp. Q1 was also capable of growth on 2-hydroxyquinoline, pyridin e, 2,3-dimethylpyridine, catechol, benzoate, and protocatechuic acid, suggesting a diverse capacity for aromatic ring degradation. Concentra tions of quinoline in excess of 3.88 mM were toxic. Although ring nitr ogen was released into the growth medium as ammonium, quinoline degrad ation was not limited by the availability of inorganic N. A degradatio n product was isolated and identified as 2-hydroxyquinoline on the bas is of ultraviolet, fluorescence emission, and mass spectroscopy. When grown on quinoline or 2-hydroxyquinoline, this bacterium produced pigm ented compounds. Copyright (C) 1996 Published by Elsevier Science Limi ted.