Chemicals can be synthesized from renewable resources using microbes. This approach could help the chemical industry become more sustainable. A major hurdle to the widespread implementation of this strategy is low production efficiency on the part of the cells. The standard approach to overcome this has been to modify the flow of carbon through cell metabolism. In this project, the flow of electrons through the cell will be adjusted. This will be accomplished by creating artificial electron shuttle molecules, known as cofactors. This is an innovative strategy. It could greatly increase the efficiency of using microbes to manufacture chemicals. Outreach activities will be integrated with the research tasks. As a result, the project represents an attempt to (i) allow biomanufacturing to better meet the Nation's needs for energy, food, commodities, and medicine; (ii) contribute to undergraduate and graduate education in STEM; and (iii) motivate female high school students in Orange County to pursue a career in engineering.
Catabolism and anabolism co-exist without interference because each has a separate redox cofactor. A third, independent redox cofactor may enable a specific pathway to be insulated from core metabolism. Increased productivity might be achieved by establishing the new redox cofactor and evolving enzymes in the product pathway to require that cofactor exclusively. This project will establish nicotinamide mononucleotide (NMN) as the third redox cofactor. This will be accomplished through a three-step experimental plan. First, high-throughput selection platforms for engineering of NMN-dependent electron circuits will be developed. Then, strains of E. coli and S. cerevisiae capable of overproduction of NMN will be constructed. Finally, NMN-dependent formate dehydrogenase will be engineered to deliver NMN reducing power independently of the host's metabolic background. Successful completion of these objectives will result in two industrially-relevant strains capable of acting as a chassis for NMN-dependent pathways and products.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
