An Evaluation of Steam Explosion Pretreatment to Enhance the Digestibility of Lignocellulosic Biomass

Pretreatment is an essential step and represents one of the main economic costs in any lignocellulosic biorefinery processes. Although numerous pretreatment methods are available, steam explosion is recognized as one of the most widely applied physicochemical pretreatment methods. Steam explosion pretreatment seems to be a promising approach to fractionate and augment the digestibility of lignocellulosic biomass with lower environmental impact and higher energy efficiency. In the current situation, there are few limitations in using steam explosion as an effective pretreatment for lignocellulosic biorefinery processes. The most important limiting factors are lower delignification rates and sugar yields in the enzymatic hydrolysis of cellulosic biomass. These issues can be addressed by using a combined pretreatment strategy involving steam explosion as the first step to fractionate lignocellulose constituents such as cellulose, hemicellulose, and lignin. The second pretreatment step should efficiently delignify the biomass and facilitate augmented enzymatic saccharification of the cellulosic fraction.