Differential bioavailability of soil-sorbed naphthalene to two bacterial species
- Michigan State Univ., East Lansing (United States)
Prediction of the fate of hydrophobic organic contaminants in soils is complicated by the competing processes of sorption and biodegradation. To test the hypothesis that sorbed naphthalene is unavailable to degradative microorganisms, the authors developed a simple kinetic method to examine the rates and extents of naphthalene degradation in soil-free and soil-containing systems in a comparison of two bacterial species. The method is predicated on the first-order dependence of the initial mineralization rate on the naphthalene concentration when the latter is below the Michaelis-Menten half-saturation constant (K{sub m}) for naphthalene for the organism under study. Rates and extents of mineralization were estimated by nonlinear regression analysis of data by using both a simple first-order model and a three-parameter, coupled degradation-desorption model described for the first time here. Bioavailability assays with two bacterial species (Pseudomonas putida ATCC 17484 and a gram-negative soil isolate, designated NP-Alk) gave dramatically different results. For Np-Alk, sorption limited both the rate and extent of naphthalene mineralization, in accordance with values predicted on the basis of the equilibrium aqueous-phase naphthalene concentrations. For strain 17484, both the rates and extents of naphthalene mineralization exceeded the predicted values and resulted in enhanced rates of naphthalene desorption from the soils. They conclude that there are important organism-specific properties which make generalizations regarding the bioavailability of sorbed substrates inappropriate.
- DOE Contract Number:
- FG02-89ER60809
- OSTI ID:
- 7303366
- Journal Information:
- Applied and Environmental Microbiology; (United States), Vol. 58:4; ISSN 0099-2240
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
NAPHTHALENE
BIOLOGICAL AVAILABILITY
BIOCHEMICAL REACTION KINETICS
BIODEGRADATION
MINERALIZATION
PSEUDOMONAS
REGRESSION ANALYSIS
SOILS
SORPTION
AROMATICS
BACTERIA
CHEMICAL REACTIONS
CONDENSED AROMATICS
DECOMPOSITION
HYDROCARBONS
KINETICS
MATHEMATICS
MICROORGANISMS
ORGANIC COMPOUNDS
REACTION KINETICS
STATISTICS
540220* - Environment
Terrestrial- Chemicals Monitoring & Transport- (1990-)
560300 - Chemicals Metabolism & Toxicology