Abstract:

In this study, protoplast fusants between Tsingdao brewer’s yeast and high-gravity yeast were developed and
preliminarily screened for their copper resistance. On the basis of this investigation, secondary screening was carried out
on a laboratory scale or in a 100 L fermentor with respect to pressure tolerance and fermentation performance. The results
showed that the selected fusant strain was superior to Tsingdao brewer’s yeast, as manifested by higher alcohol peaks as well
as faster sugar consumption and diacetyl reduction. Moreover, both yeast strains presented similar flavor compounds profile
during metabolism. The total chromosomal DNA fingerprinting of the fusant strain after 8 successive passages remained
consistent, suggesting high genetic stability.

Key words: protoplast fusion, high-gravity yeast, Tsingdao brewer’s yeast, breeding, high-gravity brewing