Chapter 6 - Use of Ultrasound for Pretreatment of Biomass and Subsequent Hydrolysis and Fermentation

Abstract

Significant attention has been given to various pretreatment techniques for the fractionation of lignocellulosic biomass for intensifying the production of biofuels. Lignocellulosic biomass as a feedstock is abundant, inexpensive, and evenly distributed in nature. However, biofuel production from lignocellulosic biomass is not commercialized at a large scale (with favorable economics), owing to barriers in the processing and higher costs of production. The present work is focused on the analysis of an ultrasound-assisted approach for the intensified fractionation of the biomass and subsequent transformation of cellulose to fermentable sugars and fermentation. The application of ultrasound can complement the prevailing lignocellulosic biomass pretreatment approaches such as alkali treatment, resulting in enhancement in the performance and efficiency. An overview of the basics of ultrasound, reactor designs, operating parameters, and challenges related to the application of ultrasound in the lignocellulosic biomass fractionation as well as subsequent hydrolysis and fermentation and its future perspectives have been provided in this chapter. Ultrasound-assisted approaches result in the reduction in treatment time and also reduce the chemical/enzyme requirement. Overall, the ultrasound-assisted approach is considered to be a novel and environmentally friendly green technique, giving a significant degree of intensification.