Kinetic study on ethanol production using Saccharomyces cerevisiae ITV-01 yeast isolated from sugar cane molasses

BACKGROUND: Bio-ethanol production from renewable sources, such as sugar cane, makes it a biofuel that is both renewable and environmentally friendly. One of the strategies to reduce production costs and to make ethanol fuel economically competitive with fossil fuels could be the use of wild yeast with osmotolerance, ethanol resistance and low nutritional requirements. The aim of this work was to investigate the kinetics of ethanol fermentation using Saccharomyces cerevisiae ITV-01 yeast strain in a batch system at different glucose and ethanol concentrations, pH values and temperature in order to determine the optimum fermentation conditions. RESULTS: This strain showed osmotolerance (its specific growth rate (mu(max)) remained unchanged at glucose concentrations between 100 and 200 g L-1) as well as ethanol resistance (it was able to grow at 10% v/v ethanol). Activation energy (Ea) and Q(10) values calculated at temperatures between 27 and 39 degrees C, pH 3.5, was 15.6 kcal mol(-1) (with a pre-exponential factor of 3.8 x 10(12) h(-1) (R-2 = 0.94)) and 3.93 respectively, indicating that this system is biologically limited. CONCLUSIONS: The optimal conditions for ethanol production were pH 3.5, 30 degrees C and initial glucose concentration 150 g L-1. In this case, a maximum ethanol concentration of 58.4 g L-1, ethanol productivity of 1.8 g L-1 h(-1) and ethanol yield of 0.41 g g(-1) were obtained. (C) 2010 Society of Chemical Industry