摘要
研究温度对酒精酵母GJ2008果糖与葡萄糖混合发酵过程的影响，旨在为甘蔗汁酒精发酵提供参考和依据。在20～36℃温度条件下，以YPDF基础培养基模拟甘蔗汁进行酒精发酵，测定发酵过程中各参数的变化，并对果糖与葡萄糖消耗过程进行曲线拟合，从拟合方程计算出果糖与葡萄糖代谢一半和代谢完全所需的时间。结果表明，温度为20～36℃时，酵母GJ2008会始终优先利用葡萄糖，果糖的利用一直受到葡萄糖的竞争性抑制，发酵液中葡萄糖含量较低时，果糖受葡萄糖的竞争性抑制得到了解除，果糖的利用速率急剧加快。总糖含量为230 g/L左右，GJ2008果糖与葡萄糖混合发酵后期果糖代谢缓慢的主原因是由于葡萄糖的竞争性抑制作用，而非乙醇的抑制作用。温度对果糖代谢的影响小于对葡萄糖代谢的影响，较低温度对果糖后期代谢缓慢现象有所缓解。最适发酵温度为28℃，发酵时间为28 h，乙醇产率为3.89 g/L＆#183;h。
To solve the problems associated with sluggish and stuck sugarcane fermentation due to high levels of residual fructose, it is necessary to find the reasons why yeast stop using fructose during late fermentation stage. In the experiments, YPDF culture medium was used to simulate ethanol fermentation by sugarcane juice at six different temperatures ranging from 20 ℃ to 36 ℃, and the change of each parameter along the fermentation process was determined, then curve fitting of fructose consumption and glucose consumption was done, and complete metabolism/half metabolism time of glucose/fructose was calculated through the fitting equation. We found that temperature had an important impact on fructose and glucose consumption, S.cerevisiae GJ2008 always showed a slightly higher preference for glucose than fructose at temperature ranging from 20 ℃ to 36 ℃, but once glucose was low enough, fructose consumption sped up drastically due to the competitive inhibition released by glucose. The main reason why fructose utilization stuck we could explain is the competitive inhibition produced by the presence of glucose during the late stage of fructose and glucose co-fermentation. Meanwhile, fructose was less strongly affected by temperature decrease and lower temperature could relieve sluggish phenomenon. The optimum temperature for maximum ethanol production in YPDF medium was at 28℃ （fermenting time was 28 h） with ethanol yield of 3.89 g/L？h. Those data are important for industrial assessment of sugarcane fermentation.
出处
《酿酒科技》
北大核心
2014年第8期19-23,共5页
Liquor-Making Science & Technology
基金
广西科技攻关项目(桂科攻0782003-2)
广西科技大学科学基金(校科自1307105)
关键词
温度
果糖
葡萄糖
酒精发酵
酵母GJ2008
temperature
fructose
glucose
ethanol fermentation
Saccharomyces cerevisiae GJ2008
