April 23, 2009

Study Reveals How to Make Gasoline from Yeast and Bacterium

By Susan Levings A chemical precursor molecule of gasoline can be produced from biomass and salt, according to research by UCSF School of Pharmacy's Christopher Voigt, PhD, and UCSF colleagues. In this case, the precursor is methyl halide, and the gasoline derived from it through catalytic conversion is chemically indistinguishable from that produced from petroleum and would not require new vehicle engines, according to Voigt. In addition to gasoline, methyl halides can also be converted to other industrial fuels and chemicals. Voigt's approach to methyl halide production uses cellulose-rich, non-food crop waste or grasses and consequently would not displace food-producing crops.

(left to right) Research team members Daniel Widmaier, Travis Bayer, principle investigator Christopher Voigt, Ethan Mirsky, and Karsten Temme in the Voigt Lab at the University of California, San Francisco Mission Bay Campus. Missing from the photo is Daniel Santi.

The results of this research were published online April 20, 2009 by the Journal of the American Chemical Society and have subsequently attracted international media attention. Voigt, who is a professor in the Department of Pharmaceutical Chemistry, is the principle investigator of the study. Team members are postdoctoral fellow Travis Bayer, PhD; PhD graduate students Daniel Widmaier, Karsten Temme, and Ethan Mirsky; and pharmaceutical chemistry faculty member Daniel Santi, PhD. Using tools from synthetic biology, the group programmed the DNA of yeast to produce methyl halides from biomass and salt. In doing so, they created an artificial symbiotic relationship between a bacterium and yeast. The bacterium, which was originally isolated from a French garbage dump, can eat non-food agricultural waste and convert it to a form that the yeast can then turn into methyl halides. Methyl halides have been extensively explored as an intermediate for the conversion of natural gas to gasoline, but they have been completely overlooked as potential building blocks from biomass, says Voigt. This is the first study to combine a yeast and a bacterium in fermentation to produce a fuel precursor from agricultural waste. "If this process were scaled up, we could potentially supplement or replace our dependence on non-renewable petroleum-based fuels and do so in an environmentally responsible way," explains Voigt who estimates that a pilot plant could be ready for construction in about three years, pending the availability of funding. The study behind Voigt's current Journal of the American Chemical Society paper was funded primarily through private support received by Voigt from the David & Lucile Packard Foundation through a 2006 Packard Fellowship for Science and Engineering. These awards are intended to allow the nation's most promising professors to pursue science and engineering research early in their careers with few funding restrictions and limited paperwork requirements. Voigt is a faculty affiliate of the University of California's California Institute for Quantitative Biosciences, which aims to integrate and expand the understanding of biological systems by using the quantitative tools and techniques of chemisty, engineering, math, and physics. Image credit: © majedphoto.com

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