Population Densities of Native MTBE-degrading Bacteria and Microbial Community Composition as a Function of MTBE Concentration in Field Columns

摘要

In an MTBE-contaminated aquifer in North Hollywood California, an ex situ field-scale bioreactor self-colonized by native strains of the known MTBE-degrader Methylibium petrolphilum PM1 has been effectively treating the underlying MTBE plume for 2.5 years. As a followup to this study, a series of field column experiments were conducted to evaluate changes in the microbial community and in the densities of naturally-occurring MTBE-degrading bacteria in response to MTBE concentration. For 8 weeks, columns packed with granular activated carbon were continuously fed groundwater from the North Hollywood aquifer. Each triplicate set also received a feed of either 0.1, 1, 10, or 20 mg/L MTBE. Denaturing Gel Gradient Electrophoresis (DGGE) was performed for the GAC-associated bacterial communities in each column. A strong shift in the dominant microbial community was observed between columns with high and low MTBE loading rates.