SBIR Phase II: Engineering brewer's yeast for enhanced flavor production during fermentation

The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase II project is to develop engineered brewer's yeast to produce hop flavor compounds during beer fermentation, so as to replace the need for agriculturally produced hops. Using agriculturally produced hops as a flavor component poses several challenges: 1) hops farming is natural resource intensive, 2) flavors imparted by hops are inconsistent from batch-to-batch, 3) lengthy agriculture timelines decouple demand from supply, and 4) new flavor varieties are restricted by slow and capital intensive hops breeding programs. This project establishes a product development framework for engineering brewer's yeast to produce flavor compounds during fermentation that are matched to consumer preferences. The technology developed during this project will allow for sustainable, consistent, on-demand production of hop flavors, and, in addition, may be extended to additional flavors and other fermentable products. This SBIR Phase II project will develop engineered brewer's yeast for production of flavor compounds that are ordinarily derived from hops. At present, the beer industry relies on agriculturally produced hops to impart organoleptically rich flavors and character to beer. Engineered yeast strains will serve as a drop-in replacement for conventional brewing strains, in that they both ferment beer and produce flavor compounds at concentrations desired in the finished beer. By applying an agile development framework towards yeast strain development, new brewer's yeast strains will be generated that produce flavor bouquets preferred by brewers and consumers. Genes that encode biosynthetic pathways for production of flavor compounds will be incorporated into brewer's yeast, and various gene regulatory programs will be tested that give rise to myriad flavor bouquets in finished beer. Strains will be initially evaluated in small-scale micro-aerobic fermentations and analyzed by GC/MS to screen for relevant flavor compound concentrations. Based on screening results, strains with desired target flavor compound concentrations will be used to produce beer at industrial pilot scale for evaluation by sensory analysis panels as a means of generating consumer feedback. This workflow will be deployed in an iterative fashion to optimize the performance of the hops flavor-producing brewer's yeast. 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.