Diesel produced from sugar using long-abandoned fermentation process
London, November 8 (ANI)
University of California, Berkeley, scientists have discovered that a long-abandoned fermentation process once used to turn starch into explosives can be used to produce renewable diesel fuel to replace the fossil fuels now used in transportation.
Campus chemists and chemical engineers teamed up to produce diesel fuel from the products of a bacterial fermentation discovered nearly 100 years ago by the first president of Israel, chemist Chaim Weizmann.
The retooled process produces a mix of products that contain more energy per gallon than ethanol that is used today in transportation fuels and could be commercialised within 5-10 years.
While the fuel's cost is still higher than diesel or gasoline made from fossil fuels, the scientists said the process would drastically reduce greenhouse gas emissions from transportation, one of the major contributors to global climate change.
"What I am really excited about is that this is a fundamentally different way of taking feedstocks and #65533; sugar or starch and #65533; and making all sorts of renewable things, from fuels to commodity chemicals like plastics," said Dean Toste, UC Berkeley professor of chemistry and co-author of a report on the new development.
The work by Toste, co-authors Harvey Blanch and Douglas Clark, UC Berkeley professors of chemical and biomolecular engineering, and their colleagues was supported by the Energy Biosciences Institute, a collaboration between UC Berkeley, Lawrence Berkeley National Laboratory and the University of Illinois at Urbana Champaign, and funded by the energy firm BP.
The linkage between Toste, whose EBI work is in the development of novel catalysts, and Clark and Branch, who are working on cellulose hydrolysis and fermentation, was first suggested by BP chemical engineer Paul Willems, EBI associate director. The collaboration, Willems said, illustrates the potential value that can come from academic-industry partnerships like the EBI.
The late Weizmann's process employs the bacterium Clostridium acetobutylicum to ferment sugars into acetone, butanol and ethanol. Blanch and Clark developed a way of extracting the acetone and butanol from the fermentation mixture while leaving most of the ethanol behind, while Toste developed a catalyst that converted this ideally-proportioned brew into a mix of long-chain hydrocarbons that resembles the combination of hydrocarbons in diesel fuel.
Tests showed that it burned about as well as normal petroleum-based diesel fuel.
"It looks very compatible with diesel, and can be blended like diesel to suit summer or winter driving conditions in different states," said Blanch.
The process is versatile enough to use a broad range of renewable starting materials, from corn sugar (glucose) and cane sugar (sucrose) to starch, and would work with non-food feedstocks such as grass, trees or field waste in cellulosic processes.
The fermentation process, dubbed ABE for the three chemicals produced, was discovered by Weizmann around the start of World War I in 1914, and allowed Britain to produce acetone, which was needed to manufacture cordite, used at that time as a military propellant to replace gunpowder.
The increased availability and decreased cost of petroleum soon made the process economically uncompetitive, though it was used again as a starting material for synthetic rubber during World War II. The last U.S. factory using the process to produce acetone and butanol closed in 1965.
Clark noted that diesel produced via this process could initially supply niche markets, such as the military, but that renewable fuel standards in states such as California will eventually make biologically produced diesel financially viable, especially for trucks, trains and other vehicles that need more power than battery alternatives can provide.
Detail of their work will appear in the next issue of the journal Nature.