摘要
研究了以超临界二氧化碳为介质，假丝酵母脂肪酶催化月桂酸和正丁醇酯化的反应过程中，压力、温度、酶含水量、底物浓度和种类对于反应的影响。使用了陈惠晴等，于《清华大学学报》１９９９年第６期第３１至３４页所述的方法，研究发现，压力升高使酶中的水分减少，导致酶活力的下降。升高压力会使反应底物的溶解度增加，使反应速率提高。在３４℃～６０℃范围内，温度的升高，使反应速率上升。酶中含水质量分数为４０％时，酶活性最高。正丁醇的浓度大于１００ｍｍｏｌＬ－１，对酶产生抑制；月桂酸浓度小于４０ｍｍｏｌＬ－１时，没有发现对反应的抑制。醇的分子体积越大，反应速率越小。醇的极性减小，反应速率增大。
This paper studies t he lipase catalyzed esterification of lauric acid and n butanol in supercritic al carbon dioxide. The method is the same as described in “Journal of Tsinghua Un iversity” (Qinghua Daxeu Xuebao), vol.39, No.6, pp31￣34, 1999, by CHEN Huiqing, YANG Jichu. The effect of pressure, temperature, water content of the enzym e, concentration and type of the substrates on the reaction are evaluated. Incre asing the pressure will make the hydration extend of the enzyme decrease, along with the decrease of the activity. However, the solubility of all substrates inc rease when turning the pressure from 8MPa to 20MPa, a higher reactio n rate thus is induced. In the range of 34℃￣60℃, increase of the t emperature will cause a tendency of higher reaction rate. The water contents of the enzyme h ave a great impact on the reaction. The activity of the enzyme reaches its peak at the water mass fraction of 40%. If the concentration of n butanol is greater than 100mmol/L, an obivous inhibition on the enzyme is observed. During e a ch experiment, lauric acid did not inhibit the reaction. The initial ra te increases with the extending of carbon chain in alcohol molecule. When the nu mber of carbon atom is more than 4, the reaction rate lowers down.
出处
《清华大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
1999年第6期28-30,34,共4页
Journal of Tsinghua University(Science and Technology)
基金
国家自然科学基金
关键词
超临界二氧化碳
催化反应
酯化反应
脂肪酶
supercritical carbon dioxide
enzyme catalyzed reaction
lauric ac id
esterification
