Ethanol production from the glucose-based medium in the presence of inhibitors using immobilized Saccharomyces cerevisiae in the stirred tank bioreactor and its modeling

Abstract

This study aimed to examine the influence of inhibitors including acetic acid (AA), formic acid (FA), and phenol (P) on ethanol production from the glucose-based medium using immobilized Saccharomyces cerevisiae in a bioreactor. Results showed that the highest ethanol yields and productions were determined as 45.64% and 38.10 g/L, 44.8% and 36.67 g/L, and 44.46% and 39.07 g/L by the addition of 2.5 g/L AA, 0.5 g/L FA, and 0.5 g/L P into the fermentation medium, respectively. Regarding mathematical modeling, the models MGM (AA), Huang (FA-P) were the best models to predict the experimental ethanol production. It was determined that the values forecasted with the models MMF (AA-FA), Weibull (P) agreed with the actual biomass growth. Besides, to forecast the observed values of the substrate consumption, the most suitable models were Weibull (AA-FA-P). Consequently, the immobilized-cell ethanol fermentations with inhibitors were successfully performed and their limit values were determined.