Ultrasound assisted pretreatment and hydrolysis for the production of ethanol from sugarcane bagasse

Abstract

The steady increase in energy consumption and the depletion of fossil fuels has reawakened the interest in developing alternative energy sources that can compensate the growing energy demands. This research utilizes sugarcane bagasse (SCB) as lignocellulosic raw material for the production of ethanol and ultrasound was incorporated to improve the conversion processes. The substantial reduction in pretreatment time and temperature with improved efficiency are the most attractive features of the ultrasound-assisted alkaline pretreatment. The hydrolyzate obtained was found to contain very less inhibitors, which improved the ethanol production significantly. The SCB hydrolyzate was subjected to fermentation and the yield obtained was 91.81% of theoretical ethanol yield. The hydrolysate obtained was fermented using Saccharomyces cerevisiae and about 90.66 % of the theoretical ethanol yield was observed in 48 h of fermentation. The effect of ultrasound on enzymatic hydrolysis and simultaneous saccharification and fermentation of SCB was performed. The reducing sugar and ethanol production were investigated with different concentration of cellulase, % amplitude and treatment time. The circular dichroism (CD) spectroscopy analysis was performed to determine the effect of % amplitude on and#945;-helical structure of cellulase and the results showed that the % amplitude affected the and#945;-helical structure of cellulase. The newlineresults concluded that the ethanol yield was not only regulated by substrate but also by other components. However, the hydrolyzate composition obtained from ultrasound assisted hydrolysis was not up to inhibitory level. The ultrasound enhanced both chemical and biological reactions and it would be a suitable method to improve the production of ethanol from lignocellulosic biomass. newline newline newline