||Microbial Degradation of Seven Amides by Suspended Bacterial Populations.
Steen, W. C. ;
Collette, T. W. ;
||Environmental Research Lab., Athens, GA. Office of Research and Development.
Water microbiology ;
Infrared spectroscopy ;
Molecular structure ;
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Microbial transformation rate constants were determined for seven amides in natural pond water. A second-order mathematical rate expression served as the model for describing the microbial transformation. Also investigated was the relationship between the infrared spectra and the second-order rate constants for these amides. Second-order rate constants (k2) ranged from a low of 2.0 x 10(-14) to a high of 1.1 x 10(-9) liters/organism/h for niclosamide (2',5-dichloro-4'-nitrosalicylanilide) and propachlor (2-chloro-N-isopropylacetanilide), respectively. The mechanism of degradation (i.e., microbially mediated hydrolysis) of the amides was consistent with that of other organic chemicals previously studied in a variety of natural waters. Preliminary investigations indicate that temporal variations in measured second-order rate constants are small. A simple linear regression of the infrared carbonyl-stretching frequency with log k2 gave a correlation coefficient (r2) of 0.962. (Copyright (c) 1989 American Society for Microbiology.)