THI3/BAT2基因缺失酿酒酵母菌构建及其在黄酒酿造中的应用

Construction of THI3/BAT2 Gene-deleted Saccharomyces cerevisiae and Its Application in Preparing Chinese Rice Wine

摘要:

为探究酿酒酵母支链氨基酸转氨酶编码基因（BAT2基因）和类丙酮酸脱羧酶编码基因（THI3基因）的缺失对黄酒中高级醇的影响，以酿酒酵母（Saccharomyces cerevisiae）菌XF1的单倍体XF1a7/XF1α6和THI3基因缺失菌XF1-T的单倍体XF1a7-T/XF1α6-T为原始菌，采用Cre/loxP重组系统构建了BAT2单基因缺失和THI3/BAT2双基因缺失的双倍体酵母重组菌XF1-B和XF1-TB。将XF1、XF1-B和XF1-TB进行黄酒发酵，实验结果表明，重组菌XF1-B、XF1-TB与原始菌XF1的生长性能相似、发酵性能无差异，重组菌XF1-B、XF1-TB酿造黄酒的异戊醇分别降低了18.12%、26.06%，异丁醇分别降低了35.21%、18.83%，正丙醇分别提高了15.42%、32.75%，总高级醇分别为269.59 mg/L、270.77 mg/L，分别降低了15.65%、15.28%。XF1-B和XF1-TB酿造黄酒中异戊醇/异丁醇比值分别为3.24和2.34，降低了27.78%。综上，重组菌XF1-B和XF1-TB都有效降低了黄酒中总高级醇含量，而且XF1-TB与XF1-B相比异戊醇/异丁醇比值显著降低，这能够降低黄酒“上头”的醉度，有效提高黄酒品质。

Abstract:

To investigate the effect of deleting the genes encoding branched-chain amino acid transaminase (BAT2 gene) and pyruvate decarboxylase-like enzyme (THI3 gene) in Saccharomyces cerevisiae on the high alcohol content in Chinese rice wine, the diploid yeasts XF1-B (BAT2 gene deletion) and XF1-TB (THI3 and BAT2 gene deletion) were constructed using the Cre/loxP recombination system with the haploid XF1a7/XF1α6 of XF1 and haploid XF1a7-T/XF1α6-T of XF1-T (THI3 gene deletion) as the original strains. Chinese rice wine was fermented using XF1, XF1-B, and XF1-TB under the same conditions. The growth capability of XF1-B and XF1-TB was similar to that of XF1, and the basic fermentation capability was not significantly different. The isoamyl alcohol content decreased by 18.12% and 26.06%, the isobutanol content decreased by 35.21% and 18.83%, the n-propanol content increased by 15.42% and 32.75%, and the high alcohol content decreased by 15.65% and 15.28% to 269.59 and 270.77 mg/L in the Chinese rice wine brewed using XF1-B and XF1-TB, respectively, compared with those of wine brewed using XF1. The ratio of isoamyl alcohol/isobutanol was 3.24 and 2.34 in Chinese rice wine brewed using XF1-B and XF1-TB, respectively, representing a decrease of 27.78% compared with that of wine brewed using XF1. In summary, both XF1-B and XF1-TB effectively reduced the total higher alcohol content, and XF1-TB effectively reduced the ratio of isoamyl alcohol/isobutanol in Chinese rice wine. Hence, they can weaken the intoxication degree and improve the quality of Chinese rice wine.