Optimization Modeling of Ethanol Production from Shorgum bicolor Grain: Comparison between Separate Hydrolysis Fermentation and Simultaneous Saccharification Fermentation

Abstract

Two different process configurations, simultaneous saccharification and fermentation (SSF) and separate hydrolysis and fermentation (SHF), were compared for ethanol production from Shorgum bicolor grain. Optimization modeling for glucoamylase and Zymomonas mobilis concentration in both of SSF and SHF were carried out to obtain optimal concentration of ethanol production. The optimum condition was achieved using 0.021 % v/v of glucoamylase and 30.19% v/v of Zymomonas mobilis for SHF. In contrast, the optimum condition for SSF was 0.021 % v/v of glucoamylase and 17.51% v/v of Zymomonas mobilis. The model predicted SHF processing to be superior. The superiority of SHF over SSF was confirmed experimentally, the result showed ethanol yield of SHF was 134.80 g/L and ethanol yield of SSF was 115.66 g/L after 72 hours incubation time. A high similarity was observed between the predicted and experimental results, demonstrating the accuracy of the model.

Sap from various palms as a renewable energy source for bioethanol production

“…This bacterium is claimed to exhibit a higher ethanol yield and productivity, and a higher substrate uptake compared with S. cerevisiae [3]. Sap of palmyra (B. flabellifer) has been fermented by Z. mobilis and 59 g/L of ethanol were obtained from 206 g/L of sugars, with a yield of 0.30 g ethanol/g sugars [73]. Although Z. mobilis is a facultative anaerobe, high oxygen concentrations influence its performance negatively [77], whereas S. Bioethanol production via acetic acid fermentation…”