July 20, 2011

Researchers Find Potential Key For Unlocking Biomass Energy

LANL molecular model helps expose cellulose weakness

Researchers at the U.S. Department of Energy's Los Alamos National Laboratory and Great Lakes Bioenergy Research Center have found a potential key for unlocking the energy potential from non-edible biomass materials such as corn leaves and stalks, or switch grass.


Biomass is a desirable renewable energy source because fermentable sugars within the cellulose network of plant cells can be extracted with enzymes and then converted into ethanol"”if only it were so simple. One of the key difficulties in creating biofuels from plant matter is that the cellulose tends to orient itself into a sheet-like network of highly ordered, densely packed molecules. These sheets stack upon themselves and bond together very tightly due to interactions between hydrogen atoms"”somewhat like sheets of chicken wire stacked together and secured by loops of bailing wire. This stacking and bonding arrangement prevents enzymes from directly attacking most of the individual cellulose molecules and isolating the sugar chains within them.



"Our modeling showed, and the experimental evidence confirmed, that the pretreatment reduced the strength of hydrogen bonds in the cellulosic network," said Gnanakaran. It was as if the bailing wire in the bound chicken-wire analogy had been removed and replaced more loosely with thread. This, in turn, significantly reduced the tightness of the cellulose network and left it more vulnerable to conversion into sugar by fungi-derived cellulolytic enzymes.


"This work helps address some of the potential cost barriers related to using biomass for biofuels," Gnanakaran said.

In addition to LANL, the GLBRC, and Michigan State University, the paper included collaborators from American University and the U.S. Department of Agriculture's Forest Products Laboratory in Madison, Wisconsin.


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