SBIR-STTR Award

The world needs to develop significant, viable alternatives to petroleum-based transportation fuels. In particular, ethanol fuel derived from plant sources, cellulosic ethanol, is positioned to become a significant component of the transportation fuel landscape. Ethanol is readily useable as a transportation fuel, can be blended with gasoline, reduces greenhouse gases, and can be made from cellulose - the low-cost hugely-abundant material of which plants are composed. However, the complexity and cost of the current conversion process has limited the promise of cellulosic ethanol. A recently developed process has been shown to simplify and consolidate the costliest aspects of current ethanol processing technology, thereby reducing plant capital costs and promising production cost reductions on the order of 20 percent or more. The process is based upon a naturally occurring bacterium, Clostridium phytofermentans, which is uniquely capable of directly converting cellulose and hemicellulosic components of biomass to ethanol at high efficiency. However, the optimal conditions for cellulosic ethanol production by C. phytofermentans have not yet been determined. Moreover, fermentation processes utilizing abundantly produced and readily available feedstocks will need to be demonstrated and optimized. Therefore, this project will utilize recent discoveries arising from C. phytofermentans genome analyses to develop a predictive understanding of the behavior of the microbe, in order to refine the commercialization process.

Commercial Applications and Other Benefits as described by the awardee:
Although the ethanol market originated with ethanol made from high-grade starch sources such as corn kernels, growth in the market is seen as coming from ethanol derived from cellulose, due to the relatively high cost of the starches. Produced cost-competitively, ethanol has the potential to rapidly expand into the transportation fuels market

Development of cellulosic ethanol biofuels technology has emerged as a national priority. Clostridium phytofermentans is a novel, naturally occurring microbe that directly converts a broad-range of complex lignocellulosic materials, with ethanol as its primary fermentation by-product. Because it can consolidate hydrolysis and fermentation steps, C. phytofermentans has the potential to significantly reduce the process cost of biomass-to-ethanol conversion. Its demonstrated ability to convert a variety of complex feedstocks enables wide application potential for cellulosic ethanol production. This project will: 1.) Determine the preferred pH, temperature, agitation speed, and media composition for the conversion of cellulose to ethanol by C. phytofermentans, 2.) Select a complex feedstock for subsequent investigations (Ammonia Fiber Expansion -treated corn stover), 3.) Demonstrate the conversion of corn stover to ethanol, and 4.) Perform bioreactor studies to maximize the conversion of corn stover to ethanol. Additionally, microbiological, genetic, and biochemical engineering data will be obtained that will allow us to model cellulose-to-ethanol conversion with C. phytofermentans and to use the biochemical reactor model to develop improved process conditions and microbial strains relevant to a viable biomass-to-ethanol process.

Commercial Applications and Other Benefits as described by the awardee:
The development of a metabolic model that is systematically evaluated with metabolic flux analyses and incorporates data from microbiological, biochemical, microarray gene expression profiling, plus bioreactor experiments, could greatly accelerate the pace at which this promising technology can be developed to a commercial scale.