Volume 3, Issue 1 Jan/Feb 2003

2002
2001

MTBE: A Tasty Morsel? by Patti Meagher Printer-friendly version Alvarez-Cohen joined the Engineering faculty in 1991. About UC Berkeley, she says: "I adore Berkeley. It's a terrific and amazingly diverse environment to teach and learn in." Coming here was her "ultimate act of rebellion," she says, since her parents told her it was too far away and forbade her from applying after she graduated from high school in New York. Bruce Cook photo As the saying goes, one man's meat is another man's poison. In a new twist, environmental engineers are using microbes to make meat out of man's poisons: microorganisms that can eat and biodegrade pollutants so they no longer pose a threat to the environment. At Berkeley's Department of Civil and Environmental Engineering (CEE), professor Lisa Alvarez-Cohen and her team are studying microorganisms present at contaminated aquifer sites like Seal Beach Naval Weapons Station. Through natural processes, these microorganisms can degrade or transform the hazardous toxins. Using this technique, known as in situ bioremediation, Alvarez-Cohen works with some unsavory chemicals, like gasoline additive methyl tertiary-butyl ether (MTBE) and metal cleaning solvent trichloroethylene. "It's really exciting to use molecular and cell biology techniques to solve environmental problems," she says, adding that such applications are relatively new. Alvarez-Cohen's research focus expanded to include these techniques during the past five years, spurred partly by motivated graduate students. The molecular applications became so compelling that they are now a major aspect of her research. Alvarez-Cohen holds the Fred and Claire Sauer Chair in Environmental Engineering and is one of nine UC Berkeley faculty who will speak March 1 at the third annual Berkeley in Silicon Valley symposium. Just last year she was elected a fellow of the American Academy of Microbiology and in 2001 published a major text, Environmental Engineering Science, with colleague William Nazaroff. She was originally inspired to enter environmental microbiology by its rich combination of overlapping fields, she says. "I wanted to do something profound, something that was giving back to society. I hated hospitals, so I couldn't be a doctor. But I really liked the convergence of the biological sciences with physics and math, all rolled up into one wonderful discipline oriented toward solving problems." Alvarez-Cohen's textbook, Environmental Engineering Science, was developed with William Nazaroff, based on their experience teaching a junior-level environmental engineering class at Berkeley. "In my classes, I always try to emphasize the importance of environmental engineers to human existence," she says. Courtesy Lisa Alvarez-Cohen Environmental microbiology begins with collecting field samples of pollutants and analyzing how they biodegrade, alone and in combination with other elements, through techniques like gas and liquid chromatography and stable isotope analysis. Each compound has its own unique stable isotopic signature, which changes as it biodegrades, leaving behind a trail of evidence about the compound's degradation pattern. One goal is to identify microorganisms that can metabolize pollutants at a site, in most cases by feeding off of them, while in others by breathing the compounds to break them down. "As changes in society promote production and release of new chemicals, and as improvements in analytical chemistry allow us to detect environmental contaminants with increasing sensitivity, new generations of emerging contaminants are found," Alvarez-Cohen says. "I focus on emerging contaminants whose biodegradation potential and pathways are not yet well understood." Can Lisa Alvarez-Cohen's microbiology research bring hope for Mother Earth? We want to hear from you... MTBE is no longer on her radar screen since, she says, it has "arrived" as a contaminant and its degradation pathways are now known. Early on, due to lack of interest in MTBE from funding agencies, she and her colleagues had to find creative funding sources for their work, which helped define the environmental threat associated with MTBE. They are now concentrating on two compounds, n-nitrosodimethylamine (NDMA), a carcinogenic byproduct of water and wastewater disinfection, and 1,4 dioxane, a carcinogenic solvent stabilizer. Some industry analysts maintain that groundwater contamination problems can be solved by making better underground storage tanks for gasoline and other chemicals, but Alvarez-Cohen counters that there are only two types of tanks: those that leak and those that will leak. She is frank in her assessment of the realities of environmental contamination and passionate in her need to be involved in the clean-up through innovative biological methods that work. "Environmental engineers are so important to human existence," she says. "They have saved more lives than can be counted by their role in clean water alone. Without clean water, you don't get to live long enough to die of cancer or heart disease." Lisa Alvarez-Cohen's Home Page Lab Notes is published online by the Public Affairs Office of the UC Berkeley College of Engineering. The Lab Notes mission is to illuminate groundbreaking research underway today at the College of Engineering that will dramatically change our lives tomorrow. Editor, Director of Public Affairs: Teresa Moore Writer, Researcher: David Pescovitz Designer: Robyn Altman Subscribe or send comments to the Engineering Public Affairs Office: lab-notes@coe.berkeley.edu. © 2003 UC Regents. Updated 1/24/03.