Transport and Reaction Processes in Bioremediation of Organic Contaminants. 1. Review of Bacterial Degradation and Transport

Abstract

Bioremediation of contaminants in soil and water involves a complex interplay between transport processes and biological reactions. Equilibrium physical factors such as aqueous solubility, soil adsorption, and phase partitioning indicate the transport processes that can limit bioremediation, namely the rates of interfacial transport and availability of contaminants to microbes. The physical properties of hydrophobic contaminants and the properties of biological membranes can be considered simultaneously by constructing a simple model for flux across from the aqueous phase to the cell interior. This simple model helps to reconcile the observed maximum biodegradation rates of different priority pollutants. This flux model for bioremediation suggests that the inhibition of biotransformation by alkyl substitution of aromatics may be due to transport kinetics rather than steric hindrance at the active enzymes. This report links the solubility of contaminants to the kinetics of transport across cell membranes, and thus suggests a mechanism which can control the overall activity of bioremediation processes for complex mixtures of contaminants.