乙醇利用菌株的分离鉴定及在低醇苹果酒中的应用

随着人们对自身健康的关注，低醇酒越来越受到人们的欢迎。为获得利用乙醇的菌株，利用YPD以及乙醇唯一碳源的培养基，经过多次分离与筛选，得到3株乙醇利用菌株SJ01、SJ02、SJ03，并对筛选菌株进行乙醇耐受特性的测定及乙醇利用曲线的绘制。同时，通过菌株菌落形态，细胞形态特征，结合26S rDNA 序列分析和系统发育树的构建，确定了3株分离菌的遗传学位置。结果表明：SJ01、SJ02、SJ03三株菌株的乙醇耐受浓度分别为10%、8%、9%。在唯一碳源培养基中培养20 d后，其乙醇利用率分别为39.9%、35.7%、31.8%。菌株SJ01和SJ02为Pichia kudriavzevii，菌株SJ03为Candida ethanolica。最后根据菌株能够利用乙醇作为唯一碳源生长的特性，将菌株SJ01和SJ03加入至苹果酒中进行低醇苹果酒的酿造，苹果酒的酒精度分别降低了17.5%和27.8%，且苹果酒品质得到了改善。
The popularity of low-alcohol ciders has risen owing to increasing health awareness. Here, yeast strains were repeatedly isolated and screened using culture media with yeast extract peptone dextrose (YPD) and ethanol as the sole carbon source, which resulted in the isolation of three ethanol-utilizing strains, SJ01, SJ02, and SJ03. The ethanol tolerance and ethanol-utilizing curve of the three strains were measured. In addition, the colony and cell morphology was observed, and the phylogenetic tree based on 26S rDNA sequence analysis was constructed to determine the genetic location of the isolates. The results showed that after incubation in media containing ethanol as the sole carbon source for 20 days, the ethanol utilization rates of SJ01, SJ02, and SJ03 were 39.9%, 35.7%, and 31.8%, respectively, while ethanol tolerance was 10%, 8%, and 9%, respectively. SJ01 and SJ02 were identified as Pichia kudriavzevii and SJ03 as Candida ethanolica. Finally, based on the growth characteristics of the strains with ethanol as sole carbon source, SJ01 and SJ03 were selected for the brewing of low-alcohol apple cider. The alcohol contents of apple cider were reduced by 17.5% and 27.8%, respectively, and the quality of the ciders was improved.