BIODEGRADATION OF MTBE BY BACTERIA ISOLATED FROM GASOLINE-CONTAMINATED SITES

摘要

Methyl tert- butyl ether (MTBE) has been used as a fuel oxygenate to replace lead tetraethyl. Due to gasoline spills mainly from leaking underground storage tanks, MTBE has become a prevalent contaminant in surface water, soils and sediments. Because of MTBEs high water solubility (4.8 x 104 mg/l), high vapour pressure (3.35 x 104 Pa) and low reactivity with organic matter, plumes can extend over kilometre scale distances. MTBE is often considered to be recalcitrant, although biodegradation has been reported under certain conditions. In this study we looked at the mineralization of MTBE as the sole carbon and energy source, by bacterial strains isolated from groundwater contaminated by gasoline spills. The results indicate that mixed consortia are able to degrade MTBE, although at different rates depending on the presence or absence of a solid support. This study also demonstrates that, based on morphological and metabolic studies, microbial consortia capable of degrading MTBE vary from site to site.