Colusa Biomass Energy Corporation has selected a 15-acre site within the Colusa Industrial Park (Colusa, California) for a 10-million-gallon per year cellulosic ethanol plant. Colusa expects to commission the plant in the fourth quarter of 2007.
Colusa will use approximately 120,000 tons per year of waste rice straw as the feedstock for the plant, which is located in a prime rice-producing area of the Sacramento Valley. The area—which produces about 18% of the rice grown in the United States—produces approximately 1.3 million tons of waste rice straw residue annually.
Colusa will produce ethanol, silica/sodium oxide and lignin from the waste biomass, including the waste rice straw, waste rice hulls and other cellulosics. Silica/sodium oxide is a widely used ingredient with applications in the paper industry, by detergent and soap producers and for the production of gels, catalysts and zeolytes.
The Colusa process ferments both 5-carbon and 6-carbon sugars to ethanol using an existing closed-loop fermentation system employing genetically-engineered thermophilic bacteria—Bacillus stearothermophilus—developed by Agrol, Ltd. in the UK. Colusa developed its own set of physical and chemical treatments to release the sugars from the lignocellulosic material for fermentation.