Washington, May 5 : The genome analysis of a biomass-degrading fungus has revealed that it has capabilities for improved biofuel production.
A team of government, academic, and industry researchers led by the US Department of Energy Joint Genome Institute (DOE JGI) and Los Alamos National Laboratory (LANL) did the analysis.
The study revealed that Trichoderma reesei, a champion biomass-degrading fungus, has a surprisingly minimal stock of genes that it employs to break down plant cell walls, highlighting opportunities for further improvements in enzymes customized for biofuels production.
T. reesei was discovered during World War II, when it was identified as the culprit responsible for the deterioration of fatigues and tents in the South Pacific.
This progenitor strain has since yielded variants for broad industrial applications and is known today as an abundant source of enzymes, particularly cellulases and hemicellulases, currently being explored to catalyze the deconstruction of plant cell walls as a first step towards the production of biofuels from lignocellulose.
For the research, the team compared the 34-million-nucleotide genome of T. reesei with 13 previously characterized fungi and discovered something counterintuitive.
Despite its reputation as an avid plant polysaccharide degrader, T. reesei, was found to have the smallest inventory of genes powering its robust degradation machinery.
"We were aware of T. reesei's reputation as a 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," said Diego Martinez, the study's lead author and researcher.
According to Eddy Rubin, DOE JGI Director, "The information generated from the genome of T. reesei provides us with a roadmap for accelerating research to optimize fungal strains for reducing the current prohibitively high cost of converting lignocellulose to fermentable sugars."
Improved industrial enzyme 'cocktails' from T. reseei and other fungi will enable more economical conversion of biomass from such feedstocks as the perennial grasses Miscanthus and switchgrass, wood from fast-growing trees like poplar, agricultural crop residues, and municipal waste, into next-generation biofuels.
"Through these incremental advances, we hope to eventually supplant the gasoline-dependent transportation sector of our economy with a more carbon-neutral strategy," said Rubin.
According to Joel Cherry, director of research activities in second-generation biofuels for Novozymes, one of the collaborating institutions on the study, "The sequencing of the Trichoderma reesei genome is a major step towards using renewable feedstocks for the production of fuels and chemicals."