WHAT IF WE COULD CONVERT not only corn, but also corn stover — the leaves, stalks, and cob — into ethanol? What if we could transform sugarcane bagasse to transportation fuel? Could poplar and pine trees, wheat and rice straw, or even municipal waste become a sustainable source of biofuels? If so, energy crops like fiber cane, switchgrass, and miscanthus could become our country’s strategic “oil” reserve, and Oklahoma could be the next member of OPEC. In the past, scientists using traditional chemistries have been unable to cost-effectively convert these residual plant products and energy crops to ethanol. Now, recent advances in industrial biotechnology are providing powerful new tools to solve this historic challenge.
There are at least five advantages to using cellulosic biomass as the raw material for biofuels: (1) use of non-food crops, (2) relatively low feedstock cost, (3) use of marginal lands for feedstock growth, (4) beneficial net energy balance, and (5) less fertilizer and water usage.
Biomass is a complex material composed of cellulose (30–50%), hemicellulose (20–40%), and lignin (15–30%). The exact composition varies from plant to plant. Since it is found in nearly all plant life, cellulose is the most abundant molecule on earth. Like the starch found in corn kernels, cellulose is a polymer of the sugar glucose. It forms part of the cell wall and is designed to contribute to the structural integrity of the plant. Hemicellulose is a more random and amorphous structure of connected sugars.
There are several technical and economic challenges associated with the large-scale production of ethanol from cellulosic biomass, including collection and transport of the biomass raw material, preprocessing or “pretreatment”, enzymatic conversion of pretreated plant material to sugars, and the fermentation of a mixed sugar stream.
Verenium has made advances in each of these areas over the past several years, greatly improving the likelihood that cellulosic ethanol will become a commercial reality in the very near future. In particular, we are using proprietary and unique micro-organisms, called ethanologens, to ferment cellulose and hemicellulose from multiple feedstocks into ethanol.
Verenium has also developed and continues to develop cocktails of novel, high-performance enzymes, under the brand name Fuelzyme™-CX, that convert a variety of plant materials to fermentable sugars. Towards this goal, we have formed a partnership with a U.S. Department of Energy (DOE)-sponsored consortium to develop an economical, commercial-scale process to convert starch and cellulosic biomass into fuel ethanol and other value-added chemicals. Verenium has also formed a research program with two New Zealand Crown Research Institutes, Scion and AgResearch, which could ultimately see New Zealand’s entire vehicle fleet running on New Zealand-grown and manufactured biofuels. Through a DOE-sponsored program, we continue to investigate the termite gut to identify enzymes to convert wood into sugars. Our collaborations with Syngenta have focused on enzymatically converting bagasse into biofuels.
Are there enough land resources in the U.S. to supply our growing need for biofuels? A 2005 report from the DOE and U.S. Department of Agriculture (USDA) concludes that the U.S. is capable of producing a sustainable supply of 1.3 billion tons per year of cellulosic biomass. According to the report, 1 billion tons of cellulosic biomass would be sufficient to displace 30% or more of our present petroleum consumption. In addition, the Natural Resources Defense Council reported in 2004 that cellulosic biofuels could supply more than half of the current transportation fuel needs in the United States by 2050, without decreasing the production of food and animal feed.
In June 2006, the DOE published a research roadmap for the advanced technologies needed to produce ethanol from cellulosic biomass. The DOE set a goal of producing 60 billion gallons of biofuels for transportation fuel — meeting 30% of current U.S. demand — by 2030. At current ethanol prices of approximately $2.00 per gallon, this would translate into an addressable market of a minimum of over $100 billion annually, not including market opportunities for cellulosic ethanol outside of the United States.
