SBIR Phase II: High-yield Fermentation of Sugars to Levulinic Acid

This Small Business Innovation Research Phase II project focuses on the development of a high-yield fermentation route for the production of levulinic acid (LA). LA is one of the best-suited C5 building blocks for bio-refinery production due to higher value, broad applications, and likely quick adoption by the chemical industry. During Phase I, this project has designed and experimentally validated the concept of a novel fermentation pathway for the production of LA. The focus of this Phase II work will be to transition from this technical proof-of-concept to the development of a lab-scale fermentation process. The limiting enzymatic steps in the designed pathway will first be optimized to reach levels of activity consistent with the flux/yield required for economical production. Variants of the designed pathway incorporating the original and optimized enzymes will subsequently be cloned into suitable fermentation organism(s). Using computational and experimental metabolic engineering tools, knock-out and knock-down mutations will be performed to further optimize flux/yield in the pathway while optimizing for host cell growth. This work represents the first commercial application of enzyme design to rationally engineer novel metabolic pathway that do not have any natural counterpart, bringing us closer to the dream of designer cell factories. The broader impact/commercial potential of this project is the advancement of a U.S. green chemistry industry and to allow America to take the lead in the commercial production of a new renewable chemical building block. The lack of a high-yield alternative to costly thermo-chemical processes has been preventing widespread adoption of levulinic acid (LA). Because LA can be converted, chemically or biochemically, to synthetic rubber (through isoprene and butenes), bio-fuels (such as kerosene and HMF), polymers (for instance, nylons) and polymer additives (for changing polymer characteristics), the addressable market is in excess of $20B annually. When considered as the end product, LA trades at a considerable higher price than ethanol, the current product of most commercial bio-refineries, and thus can help diversify their product offering and considerably increase their margins.