The broader impact/commercial potential of this Small Business Innovation Research (SBIR) project is to provide a sustainable, secure, and low-cost supply of established and emerging plant-based medicines. The class of molecules targeted for microbial biosynthesis are the benzylisoquinoline alkaloids, a diverse group of plant therapeutics that includes the pain-relieving opioids and the anti-cancer noscapinoids. Approximately 100,000 hectares of opium poppy are grown annually to extract more than 800 tons of opiate active pharmaceutical ingredients (APIs). This process diverts land use from food crops and consumes horticultural supplies including water, pesticides, herbicides, and nitrogen- and phosphorus-fertilizers. The existing supply chain suffers further vulnerabilities due to crop susceptibility to climate and disease, restricted growing seasons, and the logistical and security concerns associated with transporting poppy materials across the globe. This project will develop technology to manufacture medicinal opioids and plant-based medicines by yeast fermentation. The technology will allow for year-round, market-responsive production of valuable APIs in secure, local bioreactor facilities. An independent technoeconomic model shows yeast-based production will lower the cost of opiates by 10-50 fold. Furthermore, this technology will provide for diversification into the biosynthesis of rare and novel molecules for drug discovery, with indications spanning cancer, infectious, and cardiovascular diseases. This SBIR project proposes to develop baker's yeast as a scalable production system for medicinal opiates and related plant therapeutics. While much effort has been directed to establishing yeast strains that make high levels of other plant-specialized metabolites, such as terpenoids, platform strains for this diverse class of alkaloids do not exist. The key technical hurdle addressed by this project is to engineer strains capable of synthesizing high levels of the common branch point molecule, reticuline, from tyrosine. This project will use synthetic biology tools to improve existing prototype strains by 1) engineering alternative biosynthesis routes to increase pathway flux and bypass bottlenecks, 2) protecting a key unstable building block molecule from degradation by the host cell metabolism, and 3) implementing a spatial engineering approach to promote enzyme access to target substrates. The goal is to generate a platform yeast strain that will be used to target valuable molecules at commercially-relevant titers of greater than 1 g/L. The platform strain also will be used to access previously inaccessible natural benzylisoquinoline molecules, and an even greater number of non-natural derivatives. This technology will broadly transform the approach to provision, discover, and develop needed medicines and drug candidates.
