In Planta Expression of Endoglucanase in Plant Cell Walls of Tobacco and Maize

"Plant cell wall deconstruction" in the production of cellulose-ethanol from lignocellulosic biomass usually involves (1) the removal of the tight lignin wrapping surrounding the carbohydrate (cellulose/hemicellulose) fraction of the biomass; and (2) enzymatically breaking down the cellulose/hemicellulose into simple sugars (by cellulase and hemicellulase enzymes) for fermentation into ethanol. Enzymatic breakdown of cellulose (also called "saccharification" is considered to contribute to the high production cost of ethanol, due to the cost of enzymes. One strategy to decrease the cost of saccharification is to develop plants which already contain cellulose in the biomass (i.e., stalks or leaves). In this way, the feedstock can be made more easily "saccharifiable," as it would require a lesser dose of cellulase. Scientists from the National Renewable Energy Laboratory (United States) report the expression of endoglucanase (a type of cellulase that attacks the inner bonds of the cellulose fibers) in tobacco and maize. They found that the tobacco and maize plants which expressed the endoglucanase became "less recalcitrant" compared to wild-type counterparts, when subjected to enzymatic saccharification. The "reduction in recalcitrance was manifest through lower severity requirements to achieve comparable levels of conversion to wild-type biomass". The full results of the study are published in the open-access journal, Biotechnology for Biofuels (URL above).

Related information on cellulases:
http://en.wikipedia.org/wiki/Cellulase
http://www.cazypedia.org/index.php/Glycoside_Hydrolase_Family_9/Plant_endoglucanases