Production of cost-efficient cellulosic biofuels has been limited by lignin, which binds tightly to the cellulose found in plants' cell walls. But a Purdue researcher says a modifying a certain protein complex in the plant could lead to a plant that lends itself to cellulosic biofuel production without limiting yield.
Biochemistry professor Clint Chapple and fellow researchers generated a mutant Arabidopsis plant that can be converted to fermentable sugars. But it doesn't display growth stunting like similar mutants.
"This study opens the door to a whole new set of technologies we never could have imagined," Chapple said. "This finding is not the silver bullet that will suddenly make the wide-scale production of cellulosic biofuels possible, but it is a very important step forward."
How it works
Making cellulosic biofuels from the sugars in the plants' cell walls requires freeing cellulose from lignin so that it can be broken down fermented into fuel. That requires expensive and complicated pretreatment processes.
To avoid the pretreatment, scientists have probed ways of genetically modifying plants to weaken lignin's grip, but that often leaves them dwarfed and low-yielding.
"We've always known we couldn't eliminate lignin entirely," Chapple said. "If there isn't enough lignin in the cell walls, the plant's water conducting system will collapse. For the plants, it's like trying to drink a milkshake through a paper straw. They need the strength lignin provides to pull water up from their roots."
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The challenge, Chapple said, was to find a way of preserving lignin's key structural functions while preventing it from interfering with the use of cellulosic materials.