Fungus genes could point to cheap fuel: report
WASHINGTON (Reuters) - A deep green fungus best known for eating through uniforms and canvas tents during World War Two might provide a more efficient way to make biofuels such as ethanol, researchers reported on Monday.
They sequenced the complete genome of Trichoderma reesei and found important clues about how it breaks down plant fibers into the simple sugars needed to make plant-based fuel.
While its appetite for cotton and other fibrous plants caused trouble for troops in the South Pacific, the fungus might provide a way to use switchgrass and other nonfood plants to make biofuels, the researchers reported in the journal Nature Biotechnology.
One barrier to using nonfood plants to make biofuels has been the difficulty in converting them into sugar. Food crops such as corn more readily convert.
"Our analysis, coupled with the genome sequence data, provides a road map for constructing enhanced T. reesei strains for industrial applications such as biofuel production," Diego Martinez of Los Alamos National Laboratory in New Mexico and colleagues wrote.
The fungus has already been exploited commercially. "It has enjoyed a long history of safe use for industrial enzyme production," they wrote.
But the genetic analysis overturned some assumptions about how it worked.
It uses enzymes it creates to break down plant fibers into the simplest form of sugar, known as a monosaccharide. But it has fewer genes dedicated to the production of cellulose-eating enzymes than other fungi do.
"We were aware of T. reesei's reputation as producer of massive quantities of degrading enzymes. However we were surprised by how few enzyme types it produces, which suggested to us that its protein secretion system is exceptionally efficient," Martinez, who is also at the University of New Mexico, said in a statement.
T. reesei could be grown on an industrial scale to secrete its fiber-eating enzymes, which in turn could be added to pulped-up plants to produce sugar. The sugar can then be fermented by yeast to produce ethanol.
"The information contained in its genome will allow us to better understand how this organism degrades cellulose so efficiently and to understand how it produces the required enzymes so prodigiously," said Joel Cherry of Danish-based Novozymes, a biotechnology company that took part in the study.
"Using this information, it may be possible to improve both of these properties, decreasing the cost of converting cellulosic biomass to fuels and chemicals," Cherry said.
(Reporting by Maggie Fox, editing by Vicki Allen)