|Cellulase enzymes will play a critical role in the enabling of the production of cellulosic ethanol.|
BIO, the Biotechnology Industry Organization, organized a panel in Washington this week to describe the industrial biotechnology processes that enable large-scale production of cellulosic ethanol from biomass such as crop waste and switch grass. The panel included representatives from biotech and biofuel firms Diversa, Novozymes and Abengoa Bioenergy, as well as BIO itself and the Natural Resources Defense Council (NRDC).
Panelists at the event described how industrial biotechnology—called the third wave in biotechnology innovation—is using novel biotech tools to identify or improve enzymes from microbes for use in converting the hard, fibrous content of plants, primarily cellulose and lignin, to sugars.
The resulting sugars can then be fermented by biotech-improved bacteria to make ethanol transportation fuel or biobased plastics. Recently completed research on enzymes makes possible large-scale production of cellulosic ethanol from dedicated energy crops—such as switch grass—or crop wastes such as corn stover and wheat straw or rice straw at a cost competitive with that of petroleum-based fuels.
Industrial biotech is the enabling technology that will allow farmers to harvest two crops from every field—a food crop and a biomass crop for fuel production. Biotech breakthroughs mean that the nation’s breadbasket could also become the energy fields of the United States. The question is not when, but how soon this will happen.—Brent Erickson, BIO EVP for industrial and environmental biotechnology
Diversa has partnered with a consortium including DuPont, Deere & Co., the National Renewable Energy Laboratory and Michigan State University to develop a biorefinery that can produce ethanol and other products from the entire corn plant, integrating traditional grain-based ethanol production with cellulosic ethanol production from stalks and husks.
Diversa has already introduced a new alpha-amylase enzyme designed to improve the efficiency and economics of corn ethanol production. The new “Ultra-Thin” enzyme operates at high temperature and at a lower pH than other commercially available enzymes—a combination grain ethanol producers have been seeking for years. (Earlier post.)
|A key enabler of cellulosic ethanol? Source: Diversa.|
The company, along with CalTech, INBio and the DOE Joint Genome Institute, is now investigating the use of enzymes produced in microbes in termite guts to accelerate the production of cellulosic ethanol.
Termites eat wood and convert it to sugar by exploiting the metabolic capabilities of microbes inhabiting their hindguts. Conversion is fast and efficient: 95% in 24 hours or less. Once the cellulose is converted to sugar, it can be fermented.
Diversa is working on optimizing new enzymes from these sources via its directed evolution process to perform on specific cellulosic biomass feedstocks and in specific industrial conditions.
Novozymes. Enzyme cost has been a significant barrier to the production of cellulosic ethanol. In 2001, the enzyme costs as around $5.40/gallon—the most significant single cost. Through research funded by the DOE and NREL, Novozymes has successfully reduced the enzyme cost 30 fold&madsh;down to $0.10-0.18/gallon.
Enzyme cost is only one element of the process, however, and now that those costs are coming down, Novozymes is looking for improvements in the other portions of hte process: collection and storage; pre-treatment; plant and process design; yeast; and distribution and formulation.
While the private sector is making great strides in developing new biotech processes, public sector assistance must help solve technical issues and help to integrate the various parts of the value chain, according to the company.
|Site of the cellulosic ethanol plant—next to a conventional ethanol plant.|
Abengoa Bioenergy began construction of the world’s first commercial scale cellulosic ethanol plant in August 2005. (Earlier post.)
Upon its completion in 2006, the plant will process 70 tonnes of agricultural resides, such as wheat straw, every day, producing more than 1 million gallons of cellulosic ethanol annually.