Bioethanol production from pomegranate peel by simultaneous saccharification and fermentation process

Due to the high production of pomegranate peel waste in the world, and its good lignocellulosic content, this substance can be a good source for fuel bioethanol production. In this study, the simultaneous saccharification and fermentation (SSF) process was investigated and optimized for bioethanol production from pomegranate peel (PP). After hydrothermal pretreatment on pomegranate peel and separation of pectin and phenolic compounds, the SSF process was performed using cellulase and Saccharomyces cerevisiae. The effect of the four parameters of pH, temperature, solid loading, and enzyme dosage on the bioethanol production in the SSF process was investigated and optimized using the response surface methodology (RSM). Optimal process conditions were determined as follows: pH 5.65, temperature 40.3 °C, solid loading 12.8% w/v, and enzyme dosage 32.3U, under which the maximum amount of ethanol produced was 12.9 g/l. Furthermore, 90.4% of initial sugar was consumed by the yeast during the process, and the yield of ethanol production was 48.5%, which corresponds to 95.09% of the theoretical yield. The trend of changes in ethanol and sugar concentrations during the process time was also studied.