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Effect of alcohol chain length on the enzymatic resolution of racemic mandelic acid and kinetic study
Author(s) -
Pan Yang,
Tang KeWen,
He ChangQing,
Yi Wei,
Zhu Wei,
Liu YouNian
Publication year - 2014
Publication title -
biotechnology and applied biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.468
H-Index - 70
eISSN - 1470-8744
pISSN - 0885-4513
DOI - 10.1002/bab.1170
Subject(s) - chemistry , alcohol , mandelic acid , ethanol , methanol , triacylglycerol lipase , catalysis , butanol , substrate (aquarium) , kinetic resolution , lipase , michaelis–menten kinetics , organic chemistry , non competitive inhibition , enzyme , stereochemistry , enantioselective synthesis , enzyme assay , oceanography , geology
Abstract Asymmetric esterification of racemic mandelic acid (MA) was conducted in 1,2‐dichloroethane using lipase Novozym 435 as catalyst. Different alcohols were screened for esterification to achieve high conversion and enantioselectivity. The results show that ethanol is the best alcohol substrate among tested alcohols, and long‐chain alcohols show lower enantioselectivities. The effect of substrate concentrations on esterification with ethanol was studied, and the result indicates an alcohol inhibition. To examine the mechanism of the alcohol chain length effect, the ping‐pong bi‐bi mechanism with competitive alcohol inhibition was applied to build a model. By comparing the kinetic parameters of methanol, ethanol, butanol, heptanol, and octanol, it was found that both the Michaelis constant and the inhibition constant of alcohol increase with the increase in alcohol chain length, indicating that the balance between nucleophilicity and the inhibition effect is the possible reason for the highest conversion and enantioselectivity as shown by ethanol.