Microcalorimetric Investigation of the Effect of the Ionic Liquid 1-Butyl-3-Methylimidazolium Chloride on the Fermentation of Saccharomyces cerevisiae AY93161 for Lignocellulosic Ethanol Production

Abstract

The effects of ionic liquid 1-butyl-3-methylimidazolium chloride (BMIMCl) on the ethanol fermentation process of Saccharomyces cerevisiae AY93161 were investigated by using microcalorimetry. On the basis of microcalorimetric and process data, the thermokinetic parameters of the ethanol fermentation process at different BMIMCl concentrations from 0.001 to 5 gL^-1 were calculated. Compared to the control, the BMIMCl caused a decreased value of the maximum specific growth rate µ_m (from 0.226 to 0.105 h^-1), and an increased value of the maximum specific produced heat rate p_m (from 2.08 to 7.06 mWlg^-1) and the total heat output H for producing 1 g ethanol (from 990 to 1871 Jg^-1). The decreased µ_m and increased p_m and H led to lower final yeast concentration (from 3.85 to 2.39 gL^-1) and ethanol concentration (from 40.3 to 25.1 gL^-1). This gives useful information for improving the lignocellulosic ethanol production process using the ionic liquid technology.