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ARS Home » Research » Publications at this Location » Publication #62880
Title: ISOLATION, CHARACTERIZATION, AND SUBSTRATE UTILIZATION OF A QUINOLINE-DEGRADING MICROORGANISM

Author
item O'LOUGHLIN, EDWARD - OHIO STATE UNIVERSITY
item KEHRMEYER, STACI - OHIO STATE UNIVERSITY
item SIMS, GERALD

Submitted to: International Biodeterioration and Biodegradation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/29/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary: A bacterium capable of degrading three important pollutants, quinoline, pyridine, and 2,3-dimethylpyridine, was isolated from a mixture of soil and sewage sludge. The organism, identified as Rhodococcus, could use these compounds for growth under a wide range of environmental conditions. The organism appeared to completely degrade the compounds to their mineral components. When grown on quinoline, the organism made a degradation product, which we identified as 2-hydroxyquinoline, and it also produced a dark green pigment. The organism was examined for its ability to degrade numerous other pollutants, but was found to possess only limited capabilities to degrade compounds closely related to quinoline or pyridine. It did however degrade several compounds belonging to another chemical class (benzoates). Such a limited spectrum of degradative capabilities appears to be common among organisms that degrade nitrogen heterocycles, the class of pollutants that includes quinolines and pyridines. The results of this study add to our understanding of how and why quinoline is degraded by microorganisms, and may help us understand how pyridine is degraded, a phenomenon that has remained a mystery for years. Though this organism may not have promise as a tool for cleaning up sites contaminated with numerous different compounds, it may be useful for specific cases involving quinoline, pyridine, or 2,3-dimethylpyridine. The organism has been transferred to the American Type Culture Collection (assigned ATCC catalog number 49988) where it can be distributed to public and private research labs for further study or development.

Technical Abstract: A Gram (+) rod-shaped organism identified as a Rhodococcus sp. was capable of growth utilizing guinoline as the dominant carbon, energy, and nitrogen source. The isolate was able to utilize a range of organic substrates; however, among the aromatic N-heterocycles tested, only pyridine, 2, 3-dimethylpyridine, quinoline, and 2-hydroxyquinoline supported growth. Quinoline degradation was not limited by the availability of inorganic N, and ring nitrogen was released as ammonium. A metabolite was isolated and identified as 2-hydroxyquinoline on the basis of ultraviolet, fluorescence emission, and mass spectroscopy. The isolate was incapable of growth on putative metabolites other than 2-hydroxyquinoline. When grown on quinoline or 2-hydroxyquinoline, this organism produced pigmented compounds. Pigments were not produced when succinate or glucose were used as sole carbon and energy sources.