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Influence of naturally occurring humic acids on biodegradation of monosubstituted phenols by aquatic bacteria

Journal Article · · Appl. Environ. Microbiol.; (United States)
OSTI ID:5830862

Samples of the microbial community from Lake Michie, a mesotrophic reservoir in central North Carolina, were adapted to various levels (100 to 1000 ..mu..g/liter) of natural humic acids in chemostats. The humic acids were extracted from water samples from Black Lake, a highly colored lake in the coastal plain of North Carolina. After adaptation, the microbial community was tested for its ability to degrade the monosubstituted phenols m-cresol, m-aminophenol, and p-chlorophenol. Adaptation to increasing levels of humic acids significantly reduced the ability of the microbial communities to degrade all three phenols. The decline in biodegradation was accompanied by a decrease in the number of specific compound degraders in the adapted communities. Short-term exposure of the community to increasing levels of humic acids had no significant effect on the ability of the community to degrade m-cresol. Thus, the suppressive effect of humic acids on monosubstituted phenol metabolism was the result of long-term exposure to the humic materials. Increasing the levels of inorganic nutrients fed to the chemostats during the humic acids, indicating that nutrient limitation was probably not responsible for the metabolic suppression. The results of the study suggest that long-term exposure to humic acids can reduce the ability of microbial communities to respond to monosubstituted phenols.

Research Organization:
Univ. of North Carolina, Chapel Hill
OSTI ID:
5830862
Journal Information:
Appl. Environ. Microbiol.; (United States), Journal Name: Appl. Environ. Microbiol.; (United States) Vol. 49:2; ISSN AEMID
Country of Publication:
United States
Language:
English