Optimization of ethanol production by Zymomonas mobilis in sugar cane molasses fermentation

Abstract

The present study aimed at the optimization of the ethanol production by Zymomonas mobilis CP4, during the fermentation of sugar cane molasses. As for the optimization process, the response surface methodology was applied, using a 33 incomplete factorial design, being the independent variables: total reducing sugar (TRS) concentration in the molasses from 10, 55 and 100 g/L (x1); yeast extract concentration from 2, 11 and 20 g/L (x2), and fermentation time from 6, 15 and 24 hours (x3). The dependant variables or answers were the production and productivity of ethanol. By the analysis of the results, a good adjustment of the model to the experimental data was obtained. In the levels studied, the best condition for the production of ethanol was with 100 g/L TRS in the syrup, 2.0 g/L of yeast extract and the fermentation time between 20 and 24 hours, producing 30 g/L of ethanol.

Keywords

• Ethanol
• Zymomonas mobilis
• Molasses
• Factorial Design