Biodegradation of methyl t-butyl ether by pure bacterial cultures

Abstract

Three pure bacterial cultures degrading methyl t-butyl ether (MTBE) were isolated from activated sludge and fruit of the Gingko tree. They have been classified as belonging to the genuses Methylobacterium, Rhodococcus, and Arthrobacter. These cultures degraded 60 ppm MTBE in 1-2 weeks of incubation at 23-25 degrees C. The growth of the isolates on MTBE as sole carbon source is very slow compared with growth on nutrient-rich medium. Uniformly-labeled [14C]MTBE was used to determine 14CO2 evolution. Within 7 days of incubation, about 8% of the initial radioactivity was evolved as 14CO2. These strains also grow on t-butanol, butyl formate, isopropanol, acetone and pyruvate as carbon sources. The presence of these compounds in combination with MTBE decreased the degradation of MTBE. The cultures pregrown on pyruvate resulted in a reduction in 14CO2 evolution from [14C]MTBE. The availability of pure cultures will allow the determination of the pathway intermediates and the rate-limiting steps in the degradation of MTBE.

Monitoring Biodegradation of Methyl tert-Butyl Ether (MTBE) Using Compound-Specific Carbon Isotope Analysis

“…In several laboratory studies, biodegradation of MTBE by aerobic bacteria has been observed (8)(9)(10)(11), while in others, MTBE was reported to be recalcitrant, in particularly under anaerobic conditions (12)(13)(14)(15). Biodegradation occurred in the presence of a cosubstrate such as linear and branched short-chain alkanes (10,16,17) or with MTBE as sole carbon and energy source (8,9,11). Cometabolic degradation of MTBE by a fungus has also been reported (16).…”

“…Since it only sorbs weakly on solids (Koc ) 11 (2)) and appears difficult to biodegrade (5), it can travel nearly unretarded in groundwater and long plumes of dissolved MTBE are frequently observed (6,7). In several laboratory studies, biodegradation of MTBE by aerobic bacteria has been observed (8)(9)(10)(11), while in others, MTBE was reported to be recalcitrant, in particularly under anaerobic conditions (12)(13)(14)(15). Biodegradation occurred in the presence of a cosubstrate such as linear and branched short-chain alkanes (10,16,17) or with MTBE as sole carbon and energy source (8,9,11).…”

Treatment of Groundwater Contaminated with PAHs, Gasoline Hydrocarbons, and Methyl tert-butyl Ether in a Laboratory Biomass-Retaining Bioreactor

“…In addition, several species of white rot fungi have been found to attack and degrade a wide spectrum of PAHs (Gramss et al 1999;Harayama 1997;Novotn y et al 1999). Most of the research on the biodegradation of MtBE has focused on aerobic microbial transformation Fortin et al 2001;Kharoune et al 2001;Mo et al 1997;Stocking et al 2000;Wilson et al 2001). However, a few studies investigated the anaerobic degradation of MtBE, mainly under sulfate-reducing (Somsamak et al 2001) and methanogenic (Stocking et al 2000) conditions.…”

Cometabolic biodegradation of methyl tert-butyl ether by a soil consortium. Effect of components present in gasoline.

“…Compounds similar in structure to MTBE and present as additives in gasoline have also been studied. Mo et al (1996) reported the biodegradation of MTBE, ETBE, and TAME by mixed cultures and by pure isolates. Studies on the enrichment of mixed cultures degrading MTBE, ETBE, TAME, TBA, and tert-amyl alcohol (TAA) as the sole carbon and energy sources have also been reported (Cowan and Park, 1996).…”