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Adaptation of aquifer microbial communities to the biodegradation of xenobiotic compounds: Influence of substrate concentration and preexposure
Author(s) -
Aelion C. Marjorie,
Dobbins Durell C.,
Pfaender Frederic K.
Publication year - 1989
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620080109
Subject(s) - biodegradation , mineralization (soil science) , environmental chemistry , xenobiotic , chemistry , adaptation (eye) , substrate (aquarium) , acclimatization , aquifer , microbial population biology , ecology , biology , groundwater , biochemistry , organic chemistry , bacteria , geology , geotechnical engineering , neuroscience , enzyme , nitrogen , genetics
Abstract Studies were conducted to examine the adaptation response of aquifer microbial communities to xenobiotic compounds and the influence of chemical preexposure in the laboratory and in situ on adaptation. Adaptation and biodegradation were assessed as mineralization and cellular incorporation of 14 C‐radiolabeled substrates. For some compounds, such as ethylene dibromide, aniline and m ‐nitrophenol, biodegradation and adaptation rates were not influenced by chemical concentration over the range tested. Biodegradation rates increased with concentration for p ‐chlorophenol, and a gradient of adaptation and biodegradation responses was observed for p ‐nitrophenol up to a threshold concentration. Acclimation to laboratory conditions decreased but did not eliminate the adaptation period to p ‐nitrophenol. Laboratory adaptation studies and examination of uncontaminated and contaminated field samples from a single aquifer indicated that adaptation was accompanied by shifts in the metabolic fate of the substrate. The increased metabolism associated with adapted communities was predominantly the result of increased mineralization. Cellular incorporation represented a significantly smaller fraction of total metabolism in the adapted versus the unadapted communities. The results indicate that the adaptation response in aquifer solids is due to a complex set of interactions that are influenced by the physiology and growth of the degrading populations.