Building Better Biofuels
"We're trying to replace fossil fuels in the liquid transportation fuels sector, so we have to use a readily available feedstock. Cellulose is the most abundant organic material on the planet," said Donohue. It consists largely of sugar polymers (glucose plus others) that can be converted to other fuels by catalytic or microbial chemistries. And these sugars come from the non-edible parts of the plants, rather than from food sources.
The challenges include getting at the sugars trapped in insoluble fibers of the cellulose wall, and the variety of cellulosics. "Plants being considered are hardwood, softwood, corn, and switchgrass. However, there's likely no one magic solution," said Donohue. One of the Center's roles is to come up with the varying solutions needed.
One of these solutions is to improve plants as bioenergy feedstocks, which is an achievable goal, according to Donohue. For example, only five genetic changes were needed to develop modern maize, or sweet corn, from the grasslike perennial teosinte.
A plant improvement under way at the GLBRC is development of a "zipper" that causes the lignin in the cellulose to break apart and release the sugars. "Lignin blocks access to cell wall polysaccharides," said Donohue. "Removing lignin requires expensive and chemically harsh pretreatments. So we are redesigning the lignin for improved deconstruction."
For the GLBRC, scientists at Pacific Northwest National Laboratory are providing high-throughput analysis of bioenergy proteins and are modeling alternative biofuel scenarios from the field to the globe.
Provided by Pacific Northwest National Laboratory