Effective factors for the performance of a co-generation system for bioethanol and electricity production via microbial fuel cell technology

A co-generation system was designed to extract the redundant electrons generated in the biofermentation process to produce electricity and bioethanol simultaneously by using a microbial fuel cell (MFC) device. The effects of process operating parameters-methylene blue (MB) concentration, substrate concentration, temperature, and anodic pH on a co-generation system of ethanol and electricity were investigated to improve energy efficiency during ethanol fermentation. The results showed that a positive correlation between the power density of the cogeneration system with substrate concentration and temperature was found over the range of 20-100 g/L and 25-35 degrees C, respectively, in which ethanol was maintained at a high production level. The neutral or acid anodic solution was preferred for the co-generation system rather than the alkaline one when considering both power out and ethanol production. By assisting MFC technology, the total energy efficiency of fermentation was improved from 91.01% to 94.21% where 0.98% additional valuable electric energy was recovered. Yeast domestication is a promising way to enhance the power performance by increasing the tolerance of yeast to MB without reducing ethanol production. The proposed co-generation system indicates that the potential application of MFC in the production of biofuel or bioproducts efficiently and sustainably.