Kinetic modeling of ethanol production by batch fermentation of sugarcane juice using immobilized yeast

Abstract

Ethanol production via the batch fermentation of sugarcane juice using immobilized yeast has been studied. The influence of glucose concentration, ethanol concentration, and cell concentration (biomass) on the process rate throughout the period of fermentation has been investigated. Initial cell concentration was found to be 4.60 g/L saccharomyces cerevisiae. Biomass, ethanol and glucose concentrations were measured at different time interval during fermentation. The experimental data obtained were fitted using a variety of models for yeast growth. The logistic model gave the best fitting and was the basis for the development of the overall kinetic model. For ethanol formation, different model based on the logistic model for yeast growth were used to fit the experimental data and the leudeking – piret model was adopted because of its good fit. The leudeking – piret model was also adopted for substrate consumption. The estimated values of the kinetic parameters in the developed model were μm=0.04216hr-1, Xm = 6.2652g/L, α = 24.87149g/g.hr, Yx/s = 0.18292g/g and m = 0.008171g/g.hr. Therefore, a model based on the logistic equation of yeast growth, growth associated production of ethanol, and consumption of glucose for biomass and maintenance was found to accurately fit the production of ethanol from sugarcane.