BIODEGRADATION OF METHYL T-BUTYL ETHER BY PURE BACTERIAL CULTURES

Three pure bacterial cultures degrading methyl t-butyl ether (MTBE) we re isolated from activated sludge and fruit of the Gingko tree. They h ave been classified as belonging to the genuses Methylobacterium, Rhod ococcus, 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 nutrie nt-rich medium. Uniformly-labeled [C-14]MTBE was used to determine (CO 2)-C-14 evolution. Within 7 days of incubation, about 8% of the initia l radioactivity was evolved as (CO2)-C-14. 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 decr eased the degradation of MTBE. The cultures pregrown on pyruvate resul ted in a reduction in (CO2)-C-14 evolution from [C-14]MTBE. The availa bility of pure cultures will allow the determination of the pathway in termediates and the rate-limiting steps in the degradation of MTBE.