Reaction kinetics of ethyl lactate synthesis from lactic acid and ethanol catalyzed by lipase

被引：0

作者：

Zhao Tiantao ^{[1
,2
,3
]}

Mang Lijie ^{[1
]}

Gao Jing ^{[2
]}

Huang Zhihong ^{[2
]}

Quan Xuejun ^{[1
]}

机构：

[1] Chongqing Inst Technol, Sch Bioengn, Chongqing 400050, Peoples R China

[2] Hebei Univ Technol, Sch Chem Engn, Tianjin 300130, Peoples R China

[3] Tongji Univ, Sch Environm Sci & Engn, Shanghai 200092, Peoples R China

来源：

CHINESE JOURNAL OF CATALYSIS | 2008年 / 29卷 / 02期

关键词：

reaction kinetics; lipase; enzyme catalysis; lactic acid; ethanol; ethyl lactate; competitive inhibition; diffusion limitation;

D O I：

暂无

中图分类号：

O69 [应用化学];

学科分类号：

081704 ;

摘要：

The reaction kinetics of lipase-catalyzed esterification of lactic acid and ethanol was studied. The reaction rate could be described in terms of a ping-pong bi-bi mechanism and double-substrate inhibition. No evidence of any diffusion limitation that affected the kinetics was detected by the comparison between the time constants for the reaction (t(R)) and diffusion (t(D)). The predicted values of the corresponding mechanism reaction fitted the experimental data very well, and the rate constants were obtained by non-linear fitting analysis. The inhibition constants for lactic acid (A) and ethanol (B) were K-iA = 10.7 mmol/L and K-iB = 275.0 mmol/L, respectively, which suggested that lactic acid, being a short-chain polar acid, caused the enzyme inactivation more seriously than ethanol. The lactic acid was concentrated in the micro-aqueous layer and caused a pH drop, leading to the enzyme inactivation in its microenvironment, and the competitive inhibition of enzyme by lactic acid existed during the lipase-catalyzed esterification reaction.

引用

页码：141 / 144

页数：4