Low-alcohol Huangjiu (LAH), which contains reduced contents of ethanol and higher alcohols, is prepared by diluting original Huangjiu that has a high ethanol content, which leads to a weakened flavor (i.e., acidity). To increase acidity and reduce higher alcohols level in LAH, the gene ALD6 encoding aldehyde dehydrogenase was expressed in yeast HJ-1 under the control of the pPGK1 promoter and terminators with varying activities (tGIC1, tPGK1 and tCPS1) by scarless replacement at BAT2 locus, yielding the engineered strains HJΔB-AG, HJΔB-AP, and HJΔB-AC. The acetate concentration produced by HJΔB-AG, HJΔB-AP, and HJΔB-AC was 1.26-, 1.84-, and 2.51-fold of that of HJ-1, respectively. Furthermore, the concentration of higher alcohols produced by HJΔB-AG, HJΔB-AP, and HJΔB-AC decreased by 39.91%, 45.55%, and 52.80%, respectively. This study resulted in the creation of promising recombinant yeast strains and introduced a method that can be used for the high-quality production of LAH by acid-producing Saccharomyces cerevisiae.

中文翻译：

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通过使用无疤的ALD6过表达酵母进行发酵，可生产出具有改善的酸度和降低的高级醇含量的低酒精度黄酒。

低酒精含量的黄酒（LAH），其乙醇含量较低，而高级醇含量较低，是通过稀释高乙醇含量的原始黄酒来制备的，从而降低了风味（即酸度）。为了增加酸度并降低LAH中的较高醇含量，通过在BAT2位点进行无痕替换，在具有不同活性的pPGK1启动子和终止子（tGIC1，tPGK1和tCPS1）的控制下，在酵母HJ-1中表达了编码醛脱氢酶的ALD6基因。产生工程菌株HJΔB-AG，HJΔB-AP和HJΔB-AC。HJΔB-AG，HJΔB-AP和HJΔB-AC产生的乙酸盐浓度分别是HJ-1的1.26倍，1.84倍和2.51倍。此外，由HJΔB-AG，HJΔB-AP和HJΔB-AC产生的高级醇的浓度分别降低了39.91％，45.5％和52.80％。