This project is to develop a novel bioprocess to produce chemicals and fuels from low-cost agricultural residues such as corn stalk economically and sustainably with no CO2 emission

This Project Grant award from the U.S. Department of Agriculture National Institute of Food and Agriculture under the Small Business Innovation Research (SBIR) / Small Business Technology Transfer (STTR) Program (CFDA 10.212) supports the development of a novel bioprocess to produce n-butanol, an industrial solvent and advanced biofuel, from low-cost agricultural residues such as corn stalk. The $175,000 award to Bio-Missions LLC, a for-profit, veteran-owned limited liability company, aims to engineer a robust Clostridia strain as a superior cell factory to produce n-butanol from glucose and xylose simultaneously with high yield and productivity, while also being tolerant to hydrolysate inhibitors. The proposed integrated bioprocess involves two key fermentation steps: mixotrophic fermentation to convert glucose and formate to acetate, followed by n-butanol production from glucose, xylose, and acetate by the engineered Clostridia in a linear immobilized bioreactor with in-situ gas stripping. This approach is anticipated to achieve a 50% increase in n-butanol yield, over 10% (w/v) product titer, and substantial cost reduction to less than $2.50 per gallon, making it economically competitive as an advanced biofuel to replace ethanol.

We aim to produce n-butanol, an industrial solvent and advanced biofuel, from agricultural residues and fermentation waste gases (CO2 and H2) in an integrated bioprocess using engineered clostridia in a linear immobilized bioreactor (libr) with in-situ gas stripping for butanol recovery. Biofuel production has been limited by low product yield, productivity, and titer; whereas biorefinery using lignocellulosic feedstocks suffers from high capital and operational costs associated with pretreatments and cellulose hydrolysis, which also generate inhibitors negatively affecting fermentation performance. We have engineered a clostridia strain as a superior cell factory that not only can produce n-butanol from both glucose and xylose simultaneously with high yield and productivity, but also has a high toleranceto hydrolysate inhibitors and can use biomass hydrolysates directly without detoxification. This novel cell factory is robust for butanol production but has not been used in industrial fermentation. In addition, a novel mixotrophic fermentation with acetogen to reassimilate formate derived from CO2 released from sugars will also be developed to further increase butanol production. Phase i studies will assess the feasibility of the proposed bioprocess involving two key fermentation steps: 1) mixotrophic fermentation for converting glucose and formate to acetate with the CO-cultures of a homolactic acid bacterium and acetogen, and 2) butanol production from glucose, xylose, and acetate by engineered clostridia immobilized in libr with in-situ gas stripping. Fermentation kinetics and process performance data (titer, rate, and yield) will be collected and used in techno-economic analysis (tea) of the integrated bioprocess, which will also include biomass pretreatment/hydrolysis and pervaporation for final product purification. The proposed fermentation can achieve a 50% increase in butanol yield, >10% (w/v) product titer for energy efficient purification, and substantial cost reduction to less than $2.5/GAL, competitive for applications as industrial solvent and advanced biofuel.biobutanol is an advanced liquid fuel with an enormous potential to compete with ethanol if its production cost can be reduced to less than $2.5/GAL by using low-cost, renewable agricultural residues such as corn stalk. The proposed process can produce n-butanol at a high yield of ~0.5 g/g from lignocellulose sugars (glucose and xylose). The proposed technology thus can provide an economically competitive and superior biofuel to replace ethanol for blending in gasoline. This advanced biobutanol process can be readily adopted by the biofuels industry by retrofitting or adding onto existing bioethanol and/or corn-based acetone-butanol-ethanol (ABE) fermentation plants. IT will thus enhance the, economic viability of the rural area, where substantial amounts of lignocellulosic wastes are generated, and reduce the burden from waste biomass disposal. Successfully developing the proposed biobutanol fermentation technology will also satisfy the public interests, especially in providing a safe, renewable energy, protecting natural resources and the environment, and enhancing energy security, economic opportunity and quality of life.