Direct and Multistep Conversion of Lignin to Biofuels

Though the rapid development of human society, concerns on the fossil fuel shortage, pollution, and end-of-life disposal issues are attracting the most attention nowadays. Therefore, more efforts from governments, industries, and research institutes have been paid to the sustainable development than it has ever been done before. Cellulose, lignin and hemicellulose are the major components of biomass and also the most abundant biopolymers in nature. They are widely available, renewable, biodegradable, non-edible, and have low stable market prices which are competitive with petroleumderived polymers. Moreover, their unique structures have huge potentials to be explored. Not only being used as a raw material in pulp and paper mills, cellulose has been found to have a lot of superior properties when hydrolyzed into cellulose nanowhiskers (CNWs), which can be applied to structural materials and nanocomposites synthesis. As a major waste from the paper-making process, lignin has lead to the prosperity of the biobased chemicals and macromolecules instead of being burned directly as a low value fuel, attributing to its unique phenolic structures.