BEHAVIOR OF POLLUTANT-DEGRADING MICROORGANISMS IN AQUIFERS - PREDICTIONS FOR GENETICALLY-ENGINEERED ORGANISMS

Bioremediation via environmental introductions of degradative microorg anisms requires that the microbes survive in substantial numbers and e ffect an increase in the rate and extent of pollutant removal. Combine d field and microcosm studies were used to assess these abilities for laboratory-grown bacteria. Following introduction into a contaminated aquifer, viable cells of Pseudomonas sp. B13 were present in the conta minant plume for 447 days; die-off was rapid in pristine areas. In aqu ifer microcosms, survival of B13 and FR120, a genetically engineered d erivative of B13 having enhanced catabolic capabilities for substitute d aromatics, was comparable to B13 field results; both bacteria degrad ed target pollutants in microcosms made with aquifer samples from the aerobic zone of the pollutant plume. Results suggest that field studie s with nonrecombinant microorganisms may be coupled to laboratory stud ies with derivative strains to estimate their bioremediative efficacy. Furthermore, laboratory strains of bacteria can survive for extended periods of time in nature and thus may have important bioremediative a pplications.