高产糖苷酶非酿酒酵母菌株筛选、鉴定及其发酵过程中酶活性变化

Screening and Identification of Non-Saccharomyces Yeast Strains with High Glycosidase Production and Changes in Enzyme Activities during Their Fermentation

为探究发酵过程中本土非酿酒酵母菌株的发酵能力和糖苷酶活性,利用WL培养基、七叶苷培养基从宁夏贺兰山东麓产区自然发酵的葡萄汁中初步分选非酿酒酵母菌株;通过对硝基苯酚法测定β-D-葡萄糖苷酶、β-D-木糖苷酶、α-L-鼠李糖苷酶和α-L-阿拉伯糖苷酶活性,比较筛选高产糖苷酶菌株;并在模拟葡萄汁发酵过程中动态监测菌株的生长动力学和糖苷酶活性。结果表明:经26S rDNA的D1/D2区鉴定为Hanseniaspora opuntiae、Metschnikowia pulcherrima、3株Hanseniasporauvarum、Torulasporadelbrueckii共6株非酿酒酵母菌株具有较高的糖苷酶活性,且不同菌株间表现出一定差异性。在发酵过程中,T. delbrueckii表现出较好的发酵能力和最大的糖苷酶累积活性(94.10~127.70 mU/m L),是对照菌株的1.96~2.30倍;供试菌株M. pulcherrima具有较高的α-L-鼠李糖苷酶和α-L-阿拉伯糖苷酶活性;H. opuntiae和H. uvarum-3表现出高水平β-D-木糖苷酶和α-L-阿拉伯糖苷酶活性。本研究优选的本土非酿酒酵母具有较高的糖苷酶活性,具有葡萄酒增香酿造的应用潜力。

This study was conducted in order to explore the fermentation capacity and glycosidase activity of indigenous non-Saccharomyces isolated from naturally fermented grape juice from the eastern foothill of Helan Mountain using WL medium and esculin medium. The activity of β-D-glucosinase, β-D-xylosidase, α-L-rhamnosidase, and α-L-arabinosidase of the isolates were determined and compared using the p-nitrophenol method. The growth kinetics and glycosidase activity of six selected strains were monitored during the fermentation of synthetic grape must by each of them. The results showed that the six non-Saccharomyces strains with high glycosidase activity were identified as Hanseniaspora opuntiae, Metschnikowia pulcherrima, Hanseniaspora uvarum, and Torulaspora delbrueckii through sequence analysis of the D1/D2 domain of 26S rDNA, but their glycosidase activities were different. T. delbrueckii showed better fermentation capacity for synthetic grape must and higher cumulative glycosidase activity(94.10–127.70 mU/mL) than the other strains, which was 1.96–2.30 folds higher than the control strain. M. pulcherrima had high α-L-rhamnosidase and α-L-arabinosidase activity, while H. opuntiae and H. uvarum-3 showed high β-D-xylosidase and α-L-arabinosidase activity. In conclusion, these strains of nonSaccharomyces yeast have high glycosidase activity and possess good application potential for wine aroma enhancement.