Methodology for assessing respiration and cellular incorporation of radiolabeled substrates by soil microbial communities (journal version)
A method is described for determining biodegradation kinetics of both naturally occurring and xenobiotic compounds in surface and subsurface soil samples. The method measures both respiration and uptake into cellular biomass of 14C-labeled substrates. After separation of the cells and the soil particles by centrifugation, the cells were trapped on membrane filters for liquid scintillation counting. Mass balances were easily obtained. The technique was used to measure metabolic activity in soil profiles, including unsaturated and saturated zones. First-order rate constants were determined for amino acid metabolism and for m-cresol metabolism. Saturation kinetics were observed for amino acids and m-cresol. m-Cresol values for uptake often exceeded those for respiration by greater than a factor of ten. Saturation was not observed in many horizons. Frequently, respiration obeyed saturation kinetics, whereas uptake was first order. It is concluded that measuring only kinetics of respiration may lead to severe underestimations of biodegradation rates.
- Research Organization:
- North Carolina Univ., Chapel Hill (USA). Dept. of Environmental Sciences and Engineering
- OSTI ID:
- 6586114
- Report Number(s):
- PB-89103188/XAB
- Resource Relation:
- Other Information: Pub. in Microbial Ecology, Vol. 15, No. 3, 257-273(May 1988)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CARBON 14
TRACER TECHNIQUES
MICROORGANISMS
METABOLISM
NUTRIENTS
BIODEGRADATION
SOILS
XENOBIOTICS
KINETICS
RADIOACTIVITY
RESPIRATION
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBON ISOTOPES
CHEMICAL REACTIONS
DECOMPOSITION
EVEN-EVEN NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
NUCLEI
RADIOISOTOPES
YEARS LIVING RADIOISOTOPES
510101* - Environment
Terrestrial- Basic Studies- Radiometric Techniques- (-1989)