Cellulose-Chomping Fungus Could Boost Biofuels

Although plants and bacteria get most of the biofuel research dollars and media column inches, fungus, a kingdom of organisms that excels at breaking down fibrous cellulose, could provide some innovation for cheap and easy cellulosic biofuel production. Researchers from Los Alamos National Laboratory and the Department of Energy Joint Genome Institute have sequenced the genetic code of Tricoderma reesei, a fungal strain that was discovered during World War II when it was found to be eating through the military canvas tents and fatigues.

“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,” the study’s lead author, Diego Martinez, told Science Daily.

Novozymes, the Danish biotech giant, which controls 47 percent of the global enzyme market, collaborated on this study; it has numerous ongoing cellulosic research projects as well. Novozymes’ director of research activities in second-generation biofuels, Joel Cherry, called this achievement “a major step towards using renewable feedstocks for the production of fuels and chemicals.”

T. ressei’s enzyme-producing genes are believed to be clustered together, which researchers think could account for the fungus’ efficiency at enzyme production. This could also help with genomic splicing as geneticists could, in theory, lift entire enzyme-producing sequences and insert them into another organism, like a bacteria or yeast, to make a superbug that could efficiently break cellulose down into simple sugars and then ferment the sugars into ethanol. This is the sort of one-stop process that Mascoma is pursuing.

Photo courtesy of the DOE Joint Genome Institute.