以己酸和乙醇为底物,研究了红曲霉粗酶催化反应的动力学规律及其影响条件。研究结果表明,己酸的消耗量在0～8 h内迅速上升,随后则缓慢上升,反应24 h后,趋于平衡。过量的乙醇对反应有抑制作用,但随着己酸浓度的提高被部分解除。当己酸浓度在15.81～142.31 mmol/L,反应初速率与其浓度呈现良好的正相关性,可视为单底物反应。红曲霉粗酶含多种酶类,酶促酯化反应机理颇为复杂,其动力学关系受多种条件控制,依据试验结果建立的经验数学模型能较好地表征其粗酶酶促反应动力学特征,催化形成的主要产物为己酸乙酯,其次为辛酸乙酯、亚油酸乙酯、油酸乙酯、棕榈酸乙酯和苯乙醛,其OVA分析的结果表明,该类酶促反应的产物适合白酒等产品风格的改善。

The research on kinetics and metabolism of esterification catalyzed by Monascus esterifying enzymes were carried out with hexanoic acid and ethanol as substrates.The results showed that the consumption of hexanoic acid subsequently grew steadily after the initial stage from 0~8h in which it increased rapidly along with the reaction time,and then reached a balance after 24 h.Inhibition was noted by excessive ethanol,but relieved partially when concentration of hexanoic acid increased.Among 15.81~142.31 mmol/L of hexanoic acid concentration,single substrate reaction was identified by positive linear relation between initial velocity and concentration of hexanoic acid.The crude Monascus esterifying preparation contained various enzymes so that the empirical model could only be established according to experiment results,which could better express the kinetics characteristic of the reaction catalyzed by the crude enzyme.Ethyl hexanoate was the main product,followed by ethyl caprylate,ethyl lionleate,ethyl oleate,ethyl palmitate and phenylacetaldehyde.The results of OAV analysis indicated that esterification catalyzed by crude Monascus esterifying preparation was appropriate for improving the quality of Chinese liquor and other products.