乙醛脱氢酶基因过表达酿酒酵母在黄酒中降高级醇作用

为降低黄酒中高级醇产量，以酿酒酵母（Saccharomyces cerevisiae）单倍体菌株AY12α为出发菌，利用同源重组技术构建乙醛脱氢酶基因过表达菌株，并在不同黄酒发酵工艺下探究其对酿酒酵母产高级醇的影响。结果表明，成功构建了5株乙醛脱氢酶基因（ALD2、ALD3、ALD4、ALD5和ALD6）过表达菌株，在大米加麦曲的传统黄酒发酵工艺下，所有改造菌株均可以促进乙酸、降低高级醇的生成，其中改造菌株α-ALD6效果最显著（P＜0.01），乙酸产量是出发菌AY12α的2.92倍，总高级醇产量下降72.04%。在不同发酵工艺中，改造菌株α-ALD5与α-ALD6均可显著促进乙酸、降低高级醇生成（P＜0.01）；在纯种根霉曲做糖化剂的发酵工艺中，改造菌株在培菌糖化24 h后接入降高级醇效果更好。与纯种根霉曲相比，改造菌株以麦曲作糖化剂时降高级醇效果更好，且改造菌株α-ALD6在大米加麦曲的传统黄酒发酵工艺下降高级醇效果最好。

Effect of Saccharomyces cerevisiae overexpressing acetaldehyde dehydrogenase genes on reducing higher alcohols in Huangjiu

To reduce the production of higher alcohols in Huangjiu (Chinese rice wine), the strains overexpressing acetaldehyde dehydrogenase genes were constructed using Saccharomyces cerevisiae haploid strain AY12α by homologous recombination technology, and their effects on the production of higher alcohols under different fermentation processes of Huangjiu were studied under different fermentation processes of Huangjiu. The results showed that 5 strains overexpressing acetaldehyde dehydrogenase genes (ALD2, ALD3, ALD4, ALD5 and ALD6) were successfully constructed. All the modified strains could increase acetic acidproduction and decrease higher alcohols production under the traditional fermentation process of Huangjiu (fermentation with rice and wheat Qu). Among them, the modified strain α-ALD6 was the most effective (P＜0.01), the production of acetic acid was 2.92 times of that of the original strain AY12α, and the production of total higher alcohols decreased by 72.04%. The modified strains α-ALD5 and α-ALD6 could significantly increase acetic acid production and decrease higher alcohols production in different fermentation processes (P＜0.01). In the fermentation process with pure Rhizopus Qu as saccharifying agent, the effect of reducing the content of higher alcohols was better when modified strains were added after saccharification 24 h. Compared with pure Rhizopus Qu, the modified strains had a better effect on reducing the content of higher alcohols when wheat Qu was used as the saccharifying agent. Furthermore, the modified strains α-ALD6 had the optimal effect on reducing the content of higher alcohols under the traditional Huangjiu fermentation process (fermentation with rice and wheat Qu).