Wheat straw like any other biomass of lignocellulosic composition is a complex mixture of cellulose, hemicellulose, and lignin, as three main components, and a small amount of soluble substrates (also known as extractives) and ash. The cel­lulose strains are bundled together and tightly packed in such a way that neither water nor enzyme can penetrate through the structure [104]. Hemicellulose serves as a connection between lignin and cellulose fibers, and it is readily hydrolyzed by dilute acid or base, as well as hemicellulase enzyme. Lignin is covalently linked to cellulose and xylan (predominant hemicellulose carbohydrate polymer in wheat straw) such that lignin-cellulose-xylan interactions exert a great influence on the digestibility of lignocellulosic materials [104]. Due to this, the structural com­plexity of the lignocellulosic matrix, ethanol production from wheat straw requires at least four major unit operations including pretreatment, hydrolysis, fermenta­tion, and distillation. Unlike sucrose or starch, lignocellulosic biomass such as wheat straw need to be pretreated to make cellulose accessible for efficient enzymatic depolymerization.