Medford, Massachusetts, USA
June 29, 2010
A new generation of Agrivida's proprietary trait technology—proteins genetically engineered into the cell walls of waste corn stover and "energy crops" such as sorghum and switchgrass—increases cell wall degradation by up to 100 percent compared to non-engineered plants, while significantly decreasing enzyme loadings, following a mild pretreatment and heat activation, according to studies presented by Agrivida scientists at the World Congress on Industrial Biotechnology and Bioprocessing in Washington, DC. The meeting is sponsored by the Biotechnology Industry Organization (BIO).
The study presented at the meeting determined that embedding Agrivida's engineered enzymes in the cell walls of the crops was an effective strategy for improving the biofuels processing characteristics of the plants and dramatically decreasing external enzyme loadings, while still protecting the plants' development and growth the scientists said. The study compared the appearance, processing characteristics, and other parameters of the intein-modified plants with non-engineered, native plants.
"Agrivida transgenic corn stover was demonstrated in this study to have a conversion of more than 60 percent of cellulose to glucose, compared to approximately 30 percent seen with the control plants," following a proprietary low-cost pretreatment with heat and at reduced enzyme loadings, according to Michael Raab, Ph.D., President of Agrivida. "Further, the enzyme loadings used with Agrivida's engineered plants can be reduced well over 50 percent and still provide improved performance relative to the full enzyme loadings on non-engineered plants, thereby significantly lowering external enzyme requirements. Our new data provide additional proof that Agrivida transgenic crops can facilitate cellulose degradation in a way that greatly reduces the need for hydrolytic enzymes and expensive pretreatment processes.
This capability suggests that cellulosic ethanol production can be greatly expanded at lower costs and with fewer emissions, chemicals, and other downstream requirements." According to Raab, the ability to reduce external enzyme requirements is a critical development that should help enable the growth of the cellulosic biofuels industry. In the absence of such technology, the external enzyme production capacity build-out required to meet the U.S. Renewable Fuels Standard would exceed a cost of $5B. Agrivida's plant traits aim to eliminate those enzyme production costs for producers.
In earlier studies, Agrivida had reported that embedding CWD enzymes in plant material during the growth phase enables more efficient processing of biomass by initiating hydrolysis of plant polysaccharides from within the plant. Agrivida's enzymes are only activated only after harvest, decoupling enzyme production from hydrolysis. This enables even higher levels of expression in selected energy crops, according to Raab.
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