ABSTRACT
Bioremediation processes capitalize on the activities of aerobic or anaerobic heterotrophic microorganisms. Microbial activity is affected both qualitatively and quantitatively by a number of physicochemical environmental parameters, often referred to as ecophysiological variables. Primary metabolism of an organic compound has been defined as the use of the substrate as a source of carbon and energy for the microorganism resulting in the incorporation of organic carbon in cell matter. Thus, the substrate serves as an electron donor resulting in microbial growth. Aerobic transformations are characterized by metabolic processes involving oxygen as a reactant. Chlorinated ethenes have been found to be co-metabolized aerobically by methanotrophic microorganisms. This physiological type of bacteria thrives on the interface between aerobic and anaerobic environments in the presence of stable sources of methane such as those generated by methanogens. Microorganisms produce and excrete organic ligands, which are directly involved in the mobilization of metals.
