New technique makes biofuel from plant waste

February 3, 2014, Davis, Calif. – Gasoline-like fuels can be
made from cellulosic materials such as farm and forestry waste using a new
process invented by chemists at the University of California, Davis. The
process could open up new markets for plant-based fuels, beyond existing diesel
substitutes.

"What's exciting is that there are lots of processes to
make linear hydrocarbons, but until now nobody has been able to make branched
hydrocarbons with volatility in the gasoline range," said Mark Mascal,
professor of chemistry at UC Davis and lead author on the paper published Jan.
29 in the journal Angewandte Chemie. 

Traditional diesel fuel is made up of long, straight chains
of carbon atoms, while the molecules that make up gasoline are shorter and
branched. That means gasoline and diesel evaporate at different temperatures
and pressures, reflected in the different design of diesel and gasoline
engines.

Biodiesel, refined from plant-based oils, is already
commercially available to run modified diesel engines. A plant-based gasoline
replacement would open up a much bigger market for renewable fuels.

The feedstock for the new process is levulinic acid, which
can be produced by chemical processing of materials such as straw, corn stalks
or even municipal green waste. It's a cheap and practical starting point that
can be produced from raw biomass with high yield, Mascal said.

"Essentially it could be any cellulosic material,"
Mascal said. Because the process does not rely on fermentation, the cellulose
does not have to be converted to sugars first.

UC Davis has filed provisional patents on the process. Co-authors
on the paper are postdoctoral researchers Saikat Dutta and Inaki Gandarias.