Models for the kinetics of biodegradation of organic compounds not supporting growth

Abstract

We developed 12 models of kinetics to describe the metabolism of organic substrates that are not supporting bacterial growth. These models can be used to describe the biodegradation of organic compounds that are not supporting growth when the responsible populations are growing logistically, logarithmically, or linearly or are not increasing in numbers. Nonlinear regression analysis was used to fit patterns of mineralization by two bacteria to these kinetic models. Pseudomonas acidovorans mineralized 1 ng of phenol per ml while growing exponentially at the expense of uncharacterized organic carbon in a synthetic medium. Phenol at a concentration of 1 ng/ml did not affect the growth of P. acidovorans. These data were best fit by the model that incorporates the equation for logarithmic growth and assumes a concentration of test substrate well below its Km value. In the absence of a second substrate, glucose at concentrations below those supporting growth was mineralized by Salmonella typhimurium in a manner best described by pseudo first-order kinetics. In the presence of different concentrations of arabinose, however, the kinetics of glucose mineralization by S. typhimurium reflected linear, logistic, or logarithmic growth of the population on arabinose. We conclude that the kinetics of mineralization of organic compounds at concentrations too low to support growth are best described either by the first-order model or by models that incorporate expressions for the kinetics of growth of the metabolizing population on other substrates. When growth is at the expense of other substrates, the kinetics observed reflect such growth, as well as the concentration of the substrate of interest. The models also may be useful for analysis of the kinetics of cometabolism.

Aerobic Biodegradation of Natural and Xenobiotic Organic Compounds by Subsurface Microbial Communities

“…The objective of this study was to examine the metabolic diversity of aquifer solids microbial communities rather than to examine kinetics in detail. There have been several recent investigations of the most appropriate kinetic expressions for biodegradation rates using pure cultures [19,201, samples from aquatic environments and soil [28,29]. The results indicate that no single kinetic model is applicable for all compounds or circumstances.…”

“…This was accomplished by biodegradation assessments using radiotracer methods with six natural and nine xenobiotic organic compounds in slurries made with solids from an uncontaminated aquifer. Many different kinetic approaches are available for estimating biodegradation data [19,20]. For the purposes of this study, we evaluated the data with both first-order and Michaelis-Menten approaches.…”

Microbial Mineralization of Organic Compounds in an Acidic Agricultural Soil: Effects of Preadsorption to Various Soil Constituents

“…The mineralization models used in this study have been reported previously [7,18] and consisted of the first-order model [19], the 3/2-order model [20], and a zero-order model [21].…”

Estimation of kinetic parameter for the biotransformation of three‐ring azaarenes by the phenanthrene‐degrading strain Sphingomonas SP LH128

“…Chem. 23,2004 R. van Herwijnen et al Sphingomonas sp. strain LH128, isolated from soil samples heavily polluted with diesel oil (containing relatively high amounts of different PAHs) [8], is capable of growth on phenanthrene and, in addition, is able to cometabolize anthracene, dibenzothiophene, and fluorene.…”