Biotech giant Genencor believes so strongly in their cellulosic bioethanol process that they presented a special demonstration at the 2008 BIO World Congress, with actual, in-flask mini-experiments to show how the process works. The process is similar to bovine digestion in that it breaks complex carbohydrates into sugars that are then fermented using fungal cellulase enzymes. It begins with an acid pre-treatment, followed by enzymatic hydrolysis using their proprietary Accellerase™ 1000 enzyme, and 1-2 days of fermentation to ethanol. Their intent is that the remaining lignin can be recovered and burned for energy to power the biorefinery. Sugercane bagasse can also be used as a substrate and converted to fuel.
Genencor, a division of Danisco A/S, is an industrial biotechnology company specializing in enzymes and bioproducts that improve performance and reduce the environmental impacts of industrial processes. The company was founded in 1982 as a collaboration between Genentech and Corning Glassworks. Among the list of "firsts" achieved by this company are the first recombinant DNA enzyme produced and sold at large scale, the first commercially sold product from an extremophile, and the first mammalian gene expressed in fungi. As the second-largest biotech company in the world, Genencor employs nearly 1500 people in over 80 countries.
In order to address some of the barriers to the commercialization of cellulosic ethanol processes, Genencor developed Accellerase 1000, with multiple enzyme activities, coming from a mixture of different types of enzymes, primarily exoglucanase, endoglucasnase, hemicellulase and beta-glucosidase. Cellulose from a variety of feedstocks (sugar cane bagasse, corn stover, softwood pulp) is digested by this enzyme preparation, to yield C5 and C6 sugars.
The motivation for perfecting this technology comes from the link to the carbon cycle. How is this technology any better than refining fossil fuels? It's more sustainable because crude oil acts as a long term sink for carbon, storing it (usually) beneath the surface of the earth. When refined and burned, fossil fuels result in a net addition of carbon to the atmosphere, in the form of carbon dioxide. Instead of using fossil fuels, biofuels recycle existing atmospheric carbon dioxide which has been scavenged by plants and converted to organic matter. When this organic matter is fermented, refined and combusted, the resulting carbon dioxide that is released only replaces that which was removed. In the words of demonstrator Dr. Aaron Kelley, the plants are eventually "going to rot anyway" but we can benefit by that process, in the meantime, by using them to make biofuels.
The demonstration served to show us that the technology is certainly possible for cellulosic ethanol production, believed to be the future of biofuels. The challenge is now to optimize the process so that it can compete economically with petroleum refining. Genencor has pilot plants in the works and anticipates they will start production within the next 1-2 years.
Dr. Kelley stated the goals of Genencor are "continued technology and improvement" – certainly the goals of any successful biotechnology company. Also important to Genencor officials was to address public concerns and encourage acceptance of biofuel technology. It seems the public is generally critical of all ethanol technology regardless of the source and, in their view, it would be a shame for second-generation cellulosic technologies to be held back based on false information or preconceived notions.
When asked how much of this research was government subsidized, a discussion ensued regarding whether the US government should increase tax credits for cellulosic ethanol, and decrease credits for starch ethanol, to promote research on second generation biofuels and encourage farmers to participate. Important future goals for companies developing second-phase biofuel technologies is to improve the yield per acre of farmland, alleviate public fears due to the food versus biofuels debate and to develop and demonstrate the overall sustainability of the technology.
