Engineering of self cloning brewer’s yeast for novel terpene profiles in beer.

The Idea

Terpene flavor compounds are an important target for food improvement in a number of areas. One such area is the brewing of beer, particularly newer “craft” beers that feature large quantities of newer American varieties of hops bred for their aroma and flavor characteristics rather than their bittering properties. Beer fermentation by brewer’s yeast (Saccharomyces cerevisiae) results in changes to the profile of terpene compounds extracted from hops in a number of ways including degradation of flavor-active compounds, transformation between different classes, and hydrolysis of glycosidically bound precursors to make them flavor-active. All of these processes present targets for modification of yeast to change the profile of flavor compounds in finished beer. Genetically modifying yeastfor a food product is problematic due to EU regulations on such products but by using so-called “self-cloning” techniques to transfer sequences from one region of the yeast genome to another (i.e. cisgenesis), we can make useful modifications without creating an organism that is considered a “GMO” by current regulation. Our project will be composed of a laboratory component involving molecular biology for the creation of new yeast strains and gas chromatography combined with mass spectrometry (GC-MS) to analyze terpeneprofiles, a modeling and data analysis component in which we try to understand how terpene profiles influence flavor perception, and a legal component in which we attempt to create a legal pathway for bringing self-cloning yeast to the home brewing community.