Plant Waste Biofuels Benefit From Food Debate

In a greenhouse on the top floor of the science complex at the University of Guelph in southwestern Ontario, microbiologist Anthony Clarke stands next to rows of corn plants sprouting out of black plastic pots.

In them, he sees the future of renewable fuel — but he’s not looking at the corn kernel.
“We have all that other green matter: the leaves, the stalk, the husks even,” he said. “So the idea would be to use that material for the biofuel and the grain itself as a food.”

But turning plant waste into fuel is not easy. Plant cellulose is woven into a tight grid, making it difficult — and costly — to extract the glucose needed to make ethanol.

“There is a technology out there for biofuels from cellulosic material, but it does involve acid and steam,” said Clarke. “Both require energy to produce. So more energy is going in, currently, and expense, then is being recovered.”

With the current technology, cellulose delivers less energy than corn. But if the scientists can make their dream technology work, cellulosic ethanol could be three to eight times more energy efficient than corn ethanol.

Clarke and his colleagues are using micro-organisms that produce cellulose-munching enzymes — much like ones that let a cow digest grass — to try to make the dream a reality.

Planet Ark