UC Davis researchers have discovered a unique microbe that consumes the potentially carcinogenic fuel additive MTBE as a food source -- completely degrading the chemical within a week. The breakthrough, which would remediate environmental contamination caused by methyl tertiary-butyl ether (used to oxygenate gasoline thereby reducing polluting auto emissions), contradicts the earlier belief that MTBE is very difficult and slow to degrade, says Kate Scow, an associate professor of soil science and microbial ecology. "It has been very difficult to isolate a single bacterial species that can rapidly and completely degrade the chemical," Scow says. But Scow's bacterial microorganism, isolated by graduate student Jessica Hanson from a mixture of microorganisms able to degrade MTBE, uses MTBE as its only source of carbon and energy, and is "robust. It keeps going and doesn't fizzle out," Scow says. The microbe appears to break down the MTBE into harmless components so that the chemical literally disappears from soil and water. Hanson and Corinne Ackerman, an undergraduate student, found that when inoculated into soil, for example, the microbe rapidly degraded MTBE. This is the first example of a single microorganism capable of completely degrading MTBE without the addition of a secondary carbon source. The inoculation technique has potential to be adapted for treating MTBE-contaminated soils and groundwater. Scow's work already is bringing attention from other researchers and from petroleum companies, she says, and was mentioned recently in the journal Environmental Science and Technology. Scow is working with UC Davis civil and environmental engineering professors on bacterial mixtures that biodegrade MTBE in a variety of waste-treatment systems. Scow's group has used DNA fingerprinting techniques to show that their microbe is an important member of these MTBE-degrading organisms. Scow's research is part of an ongoing research effort by UC Davis scientists -- at the direction of the California legislature -- to study potential exposure to, and management of, the additive in the state's water. The scientists' research focuses on field studies of how MTBE spreads and biodegrades, techniques to study the additive in ecosystems, ecological risk assessment, treatment methods and policy options. Media contacts: Kate Scow, Land, Air and Water Resources, (530) 752-4632, kmscow@ucdavis.edu; Jessica Hanson, LAWR, jrhanson@ucdavis.edu; Lisa Klionsky, News Service, (530) 752-9841, lrklionsky@ucdavis.edu.