Production of Beer with a Genetically Engineered Strain of S. cerevisiae with Modified Beta Glucanase Expression

Yang Shengli^1,2,3, Liu Zhongshan², Chi Shengzhou², He Sheng², Meng Qingwei², Liu Congcong², Lin Yi² and He Guoqing^1,4
¹ Department of Biosystem Engineering and Food Sciences, Zhejiang University, Hangzhou 310029, PR China.
² Inbev Doubledeer Brewing Group, Wenzhou 325000, PR China.
³ The College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou 310014, PR China. ⁴ Corresponding author. E-mail: gqhe@zju.edu.cn.

J. Inst. Brew. 115(4), 361–367, 2009 | VIEW ARTICLE

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.

Key words:
draft beer, foam, β-glucanase, proteinase A, recombinant S. cerevisiae.