Details

Autor(en) / Beteiligte

• Zhang, Cui-Ying
• Liu, Yu-Lan
• Qi, Ya-Nan
• Zhang, Jian-Wei
• Dai, Long-Hai
• Lin, Xue
• Xiao, Dong-Guang

Titel

Increased esters and decreased higher alcohols production by engineered brewer’s yeast strains

Ist Teil von

• European food research & technology, 2013-06, Vol.236 (6), p.1009-1014

Ort / Verlag

Berlin/Heidelberg: Springer-Verlag

Erscheinungsjahr

2013

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Esters and higher alcohols produced by yeast during the fermentation of wort have the greatest impact on the smell and taste of beer. Alcohol acetyltransferase, which is mainly encoded by the ATF1 gene, is one of the most important enzymes for acetate ester synthesis. Cytosolic branched-chain amino acid aminotransferase, on the other hand, which is encoded by the BAT2 gene, plays an important role in the production of branched-chain alcohols. The objective of this study is to construct engineered brewer’s yeast strains that produce more acetate esters and less higher alcohols. Industrial brewer’s yeast strain S 5 was used as the parental strain to construct ATF1 overexpression and BAT2 deletion mutants. The engineered strains S 5-2 and S 5-4, which feature partial BAT2 allelic genes replaced by the constructed ATF1 overexpression cassette, were obtained. The ester production of the engineered strains was observed to increase significantly compared with that of the parental cells. The concentrations of ethyl acetate produced by the engineered strains S 5-2 and S 5-4 increased to 78.88 and 117.40 mg L −1 , respectively, or about 7.7-fold and 11.5-fold higher than that produced by parental S 5 cells. The isoamyl acetate produced by S 5-2 and S 5-4 also increased to 5.14 and 9.25 mg L −1 , respectively; by contrast, no isoamyl acetate was detected in the fermentation sample of the parental strain S 5. Moreover, S 5-2 and S 5-4, respectively, produced about 65 and 51 % of higher alcohols produced by the parental strain. The increase in acetate ester content and decrease in higher alcohol concentration shown by the engineered brewer’s yeast strains at the end of fermentation process indicate that the new strains are useful in future developments in the wheat beer industry.