As a source of transportation energy, advanced biofuels synthesized from lignocellulosic biomass in grasses and other non-food plants have the potential to replace fossil fuels that are responsible for the annual release of nearly 9 billion metric tons of excess carbon into the atmosphere. Unlike ethanol made from corn or sugarcane, advanced biofuels can be dropped into today's vehicles with no impact on performance, and used in today's infrastructures with no modifications required. Advanced biofuels are renewable and carbon-neutral, meaning their use does not add excess carbon to the atmosphere.
Xylan, like cellulose, is a major component of plant cell walls that serves as a valuable source of human and animal nutrition. Despite its importance, few of the enzymes that can synthesize xylan-type polysaccharides have been identified. It is believed that xylan plays an essential structural role in plant cell walls through cross-linking interactions with cellulose and other cell wall components.
"Xylan is of particular interest for the improvement of feedstocks for the generation of cellulosic biofuels, a currently expensive and inefficient process," says Ronald.
"Xylan inhibits access of the enzymes that break down cellulose into sugars and is an additional substrate for cross-linking to lignin, all of which contributes to the recalcitrance of plant cell walls."
To find genes important for grass xylan biosynthesis, Ronald, Scheller and their co-authors focused on the GT61 family of glycosyltransferases. GT61 enzymes have been identified through bioinformatics as being expanded in grasses and containing grass-specific subgroups. Working with rice plants, the standard plant model for studying grasses, they conducted a reverse genetics scree
|Contact: Lynn Yarris|
DOE/Lawrence Berkeley National Laboratory