Production of beer with a genetically engineered strain of s. cerevisiae with modified beta glucanase expression

Abstract

This study used a recombinant Saccharomyces cerevisiae strain, which expressed both β-glucanase enzyme and reduced Proteinase A expression during wort fermentations. The genetic stability and fermentation features of the strain were examined. The recombinant strain's proteinase A activity was reduced compared to the parent strain; β-glucanase was produced throughout the fermentation. The fermentation with the recombinant S. cerevisiae strain exhibited a larger reduction in β-glucan content than what was observed with the control strain, with β-glucan degradation above 80%. The foam stability period was reduced when the beer produced by the recombinant S. cerevisiae was stored for 3 months. SDS-PAGE analysis of the beer proteins indicated that lipid transfer protein 1 had disappeared. Fermentation studies indicated that based on the parameters examined, this recombinant strain was suitable for industrial beer production. © 2009 The Institute of Brewing & Distilling.