HOUSTON -- June 30, 2008 -- In a move that promises to change the economics of biodiesel refining, chemical engineers at Rice University have unveiled a set of techniques for cleanly converting problematic biofuels waste into chemicals that fetch a profit.
The latest research is available online in the journal Metabolic Engineering. The new paper and others published earlier this year describe a new fermentation process that allows E. coli and other enteric bacteria to convert glycerin -- the major waste byproduct of biodiesel production -- into formate, succinate and other valuable organic acids.
"Biodiesel producers used to sell their leftover glycerin, but the rapid increase in biodiesel production has left them paying to get rid of it," said lead researcher Ramon Gonzalez, Rice's William W. Akers Assistant Professor in Chemical and Biomolecular Engineering. "The new metabolic pathways we have uncovered paved the way for the development of new technologies for converting this waste product into high-value chemicals."
About one pound of glycerin, also known as glycerol, is created for every 10 pounds of biodiesel produced. According to the National Biodiesel Board, U.S. companies produced about 450 million gallons of biodiesel in 2007, and about 60 new plants with a production capacity of 1.2 billion gallons are slated to open by 2010.
Gonzalez's team last year announced a new method of glycerol fermentation that used E. coli to produce ethanol, another biofuel. Even though the process was very efficient, with operational costs estimated to be about 40 percent less that those of producing ethanol from corn, Gonzalez said new fermentation technologies that produce high-value chemicals like succinate and formate hold even more promise for biodiesel refiners because those chemicals are more profitable than ethanol.
"With fundamental research, we have identified the pathways and mechanisms that med
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