Author
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Sims, Gerald |
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Submitted to: American Society for Microbiology Annual Meeting
Publication Type: Abstract Only Publication Acceptance Date: 6/30/2003 Publication Date: 11/9/2003 Citation: Sims, G.K., Cupples, A.M. 2004. Role of exogenous inorganic N on biodegradation of N- heterocycles in environmental matrices. [abstract]. In: Abstracts of the 104th Annual Meeting of the American soceity for Microbiology. New Orleans, LA. No. Q-290. Interpretive Summary: Technical Abstract: Nitrogen heterocycles occur in the environment as pyridines, quinolines, acridines, indoles and related compounds, and these structures form the basis of many pharmaceuticals and agricultural chemicals. Though commonplace as contaminants, limited information is available on the environmental behavior of N-heterocycles. For most complex heterocyclic compounds, knowledge of the mechanisms of biodegradation are poorly understood, and degradative pathways, even for some simple heterocycles, such as pyridine, remain sketchy. Many N-heterocycles are inherently resistant to electrophilic attack, particularly those bearing multiple heteroatoms, and thus may be better N than C sources owing to the oxidized state of ring C. We therefore hypothesized that exogenous N may influence biodegradation of oxidized N-heterocycles in environmental matrices. Studies were performed using to examine the role of exogenous inorganic N sources on degradation of N-heterocyclic compounds in surface and subsurface materials. Either stable or radioisotopes were employed where available. Degradation of several compounds with multiple heteroatoms (atrazine, cloransulam-methyl) exhibited dependence upon exogenous N concentrations, and generally, productive agricultural soils (alfisols, mollisols) contained sufficient inorganic N even when unfertilized, to retard degradation of these compounds. Homocyclic and heterocyclic portions of the same molecule (e.g. cloransulam-methyl) responded differently to exogenous N. Some of the simpler heterocycles (pyridine, alkylpyridines) were degraded at similar rates regardless of exogenous N concentrations. Results indicate that N-hetrocyclic compounds containing oxidized ring-C are better sources of N than C. |
