研究报告
中国酿造
2016年第35卷第1期
总第287期
啤酒酵母乙醛代谢关键酶相关性研究
崔云前'王君伟1李红2*金玮翌2
（1.齐鲁工业大学生物工程学院中德啤酒技术中心，山东济南2503532.中国食品发酵工业研究院北京100015）
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摘要乙醛是啤酒中的主要风味物质其代谢主要来自酵母细胞。酵母中乙醇脱氢酶及乙醛脱氢醇是乙醛代谢的关键酶对乙醛变化起着重要作用。跟踪啤酒酵母发酵过程中相对酶活力及乙醛变化发现两种乙醇脱氢酶和乙醛脱氢酶的相对酶活力与发酵过程乙醛含量变化具有一定相关性。同时对低产乙醛啤酒酿酒酵母kb2-4与出发菌株啤酒酵母kb进行发酵试验跟踪检测相对酶活力及乙醛含量其乙醇脱氢酶I和乙醇脱氢酶Ⅱ及乙醛脱氢酶相对酶活力均高于出发菌株平均增幅分别为15.5%11.6%和5%。3种酶活性的变化协同作用可以使乙醛含量降幅最大为33.8%。
关键词之醛醇酵母醇脱氢酶之醛脱氢醇相对酶活
中图分类号：TS261.4
文章编号0254-5071(2016)01-0029-05
doi:10.11882/j.issn.02545071.2016.01.007
Correlation ofkeyenzymesof acetaldehydemetabolism inbeer yeast
CUI Yunqian', WANG Junwei', LI Hong*, JIN Weiyun
(1. College of Biological Engineering, Qilu University of Technology, China-Germany Beer Brewing Technica/ Center, Jinan 250353, China,
2.China Nationa/ Research Institute of Food and Fermentation Industry, Bejing 100015, China)
Abstract: Acetaldehyde is the main flavor substance in beer, and its metabolism mainly occurs in yeast cells. Alcohol dehydrogenase (ADH) and alde-hyde dehydrogenase (ALDH) in yeast are the key enzymes in the acetaldehyde metabolism, which plays an important role in the changes of acetalde-hyde. By tracking the relative enzyme activity and acetaldehyde changes during beer yeast fermentation process, the results showed the relative en-zyme activity of two kinds of ADH and ALDH had certain relevance with the changes of acetaldehyde content during fermentation process. At the same time, in the fermentation test of low yield acetaldehyde beer brewing yeast kb2-4 and original strain beer brewing yeast kb, the relative enzyme activity and the acetaldehyde content were determined. The relative enzyme activity of ADH I, ADH II and ALDH were higher than that of the origi-nal strain, and the average growth rates were 5%, 11.6% and 15.5%, respectively. The synergistic effect of the three kinds of enzyme activity changes could make the acetaldehyde content decreasing amplitude to the maximum of 33.8%
Key words; acetaldehyde; yeast; alcohol dehydrogenase; aldehyde dehydrogenase; relative enzyme activity
乙醛是啤酒中的主要风味物质其代谢主要来自酵母细胞。酵母中乙醇脱氢酶及乙醛脱氢酶是乙醛代谢相关的主要酶。其酶活性在整个发酵过程中的变化导致了乙醛含量的变化。酿酒醇母利用糖醇解产生乙醇的代谢过程中主要是葡萄糖经糖酵解途径(embden-meyerhof-pamasEMP)转化为丙酮酸，由丙酮酸脱羧酶催化还原生成乙醛再经乙醇脱氢酶还原生成乙醇，同时伴随着乙醇向乙醛的逆转化另外乙醛经乙醛脱氢酶转化为乙酸在酵母内整个乙醛代谢过程主要有丙酮酸脱氢酶、乙醇脱氢酶和乙醛脱氢酶的共同参与。其中乙醇脱氢酶和乙醛脱氢酶对乙醛的出路起着至关重要的作用。酿酒酵母中有5种基因编码与乙醇代谢相关联的乙醇脱氢酶分别是adh1、adh2、adh3、adh4和adh5-3]其中的4种乙醇脱氢酶作用是将乙醛还原成乙醇其中乙醇脱氢酶工起着主要
收稿日期2015-11-19
基金项目国家国际科技合作专项项目（2014DFG31770）
作用，一种乙醇脱氢酶（乙醇脱氢酶Ⅱ)是将乙醇氧化成乙醛(4。乙醛脱氢酶是丙酮酸脱氢酶（pyruvatedehydrogenase， PDH)旁路作用的第二种酶负责氧化乙醛生产乙酸5]。国内外已有众多关于醇母内乙醛脱氢酶及乙醇脱氢酶的研究,但多局限于酶的机理性质方面的研究]。酶与乙醛等代谢产物的研究多集中在引入基因工程技术定向改变啤酒酵母遗传及生理性状(-。而未对酵母内酶活性与代谢产物变化相关性进行深入探讨
在乙醇脱氢酶和乙醛脱氢酶作用下乙醛向乙醇和乙酸以及乙醇向乙醛的转化过程中涉及辅酶I(nicotinamide adenine dinucleotideNAD*)和还原型辅酶I(nicotinamide adenine dinucleotide hydrogenNADH)的相互转化。通过酶系反应中辅酶的变化可用来表示乙醇脱氢酶及乙醛脱氢酶的酶活性大小。本研究集中于乙醇脱氢酶和乙醛脱
作者简介崔云前(1969-）男副教授博士研究方向为现代啤酒酿造技术
*通讯作者李红(1978-）男高级工程师博士后研究方向为现代啤酒酿造技术
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