Yeast and Fermentation Session
jinjing wang, jiangnan university, wuxi, jiangsu, china
Co-author(s): Qi Li, Jiangnan University, Wuxi, China
ABSTRACT: Higher acetaldehyde concentration in beer is one
of the main concerns of the current beer industry in China.
Acetaldehyde is always synthesized during beer brewing by the metabolism
of yeast. Here, using ethanol as the sole carbon source and
4-methylpyrazole as the selection marker, we constructed a new mutant
strain with lower acetaldehyde production and improved ethanol tolerance
via traditional mutagenesis strategy. European Brewery Convention tube
fermentation tests comparing the fermentation broths of the mutant
strain and the industrial brewing strain showed that the acetaldehyde
concentration of the mutant strain was 81.67% lower, whereas its
resistant staling value (RSV) was 1.0-fold higher. Alcohol dehydrogenase
catalyzes the reaction of acetaldehyde formation from ethanol. Owing to
the mutation of the alcohol dehydrogenase, the alcohol dehydrogenase
activity of the mutant strain decreased to about 30% of the wild-type
strain. In the meantime, the ethanol tolerance of the mutant strain
increased by about 0.5–1% more than wild-type strain, which is very
important to yeast strain, especially under high gravity or very high
gravity fermentation conditions. The mutant strain constructed in this
work could be applied to the beer industry directly due to its better
performance in the brewing process.
Jinjing Wang received a
Ph.D. degree in genetics from the Institute of Microbiology, Beijing,
China. She spent a year and a half at Washington State University as a
visiting scholar. She began employment with Jiangnan University in 2011
as an assistant professor in the Brewing and Enzyme Technology Center of
the Biological Engineering School.
VIEW PRESENTATION 234
