Chemical-based pretreatments of lignocellulosic wastes for enhanced bioethanol production: a review

Nowadays, ethanol is the most important renewable liquid biofuel which can be produced from different raw materials to decrease the air pollution and increase the combustion efficiency. Lignocelluloses are main components in most waste streams such as those from forestry, agriculture and municipalities, and predominantly consist of cellulose, hemicelluloses and lignin. Pretreatment is a key step in producing low-cost ethanol from lignocellulosic materials since the highly crystalline cellulose is well protected by a matrix of lignin and hemicellulose in macrofibrils which decelerate the bioconversion of native cellulose. Several techniques have been developed to alter the lignocelluloses structure, among them chemical-based pretreatments such as acid, alkali are the most popular methods which can efficiently remove lignin barrier and reduce the cellulose crystallinity. The present investigation covers the most recent development of chemical-based pretreatments of lignocellulosic materials for efficient hydrolysis and bioethanol production.

Keywords:

Lignocellulose , Chemical pretreatment , Enzymatic hydrolysis , Bioethanol