Regular articleEffect of temperature on sugarcane ethanol fermentation: Kinetic modeling and validation under very-high-gravity fermentation conditions

- Ethanol fermentation by S. cerevisiae is conducted over a wide temperature range.
- A mechanistic kinetic model is developed to predict reaction rates.
- A methodology was proposed to estimate temperature-dependent kinetic parameters.
- The applicability of the kinetic model is validated for VHG ethanol fermentation.
- Conditions to produce ethanol with a higher yield and productivity are studied.

In this work, a mechanistic model is developed to simulate the effect of temperature on Saccharomyces cerevisiae growth and ethanol production of batch fermentations. A wide temperature range is used to estimate the temperature-dependent kinetic parameters of the reaction kinetics. Because multi-parameter estimation problems are complex, an optimization-based procedure is used to determine the optimum parameter values. The calculated reaction rates are used to construct a mechanistic fed-batch model. Experimental data from several cycles of very-high-gravity (VHG) ethanol fermentation from sugarcane are used to validate the model. Acceptable predictions are achieved in terms of the residual standard deviation (RSD). In addition, a suitable fermentation temperature profile, nutrient supplementation and micro-aeration during cell treatment are essential factors to obtain a yield of up to 90%, with a productivity of 10.2 g/L h and an ethanol concentration of 120 g/L.