ABSTRACT
Agrobiomass or lignocelluloses constitute virgin wood, agricultural residues, food wastes and agro-industrial wastes. Complex lignocellulosic composite structure of cellulose, hemicellulose and lignin are held together through carbon-carbon, ether, ester and hydrogen (H)-bonding. Intra-lignocellulose bonding plays an important role in interacting and holding cellulose, hemicellulose and lignin. Physical pre-treatment processes are employed without chemical agent and microorganisms. Physical pre-treatment processes are employed without chemical agent and microorganisms. In hydrothermal process, hot water under high temperature and pressure penetrates into the compact structure of biomass and hydrolyzes the lignin, hemicelluloses and celluloses by breaking the H-bond and set the constituents free. Water as a supercritical fluid is “green” with liquid-like density and gas-like transport properties, and behaves very differently than it does at room temperature.
