Chapter 2. Use of Biotechnology for Conversion of Lignocellulosic Waste into Biogas and Renewable Chemicals

The first part of this chapter will discuss the composition of lignocellulose, and the structures of the cellulose, hemicellulose and lignin components. Degradation of lignocellulose in soil and the microorganisms and enzymes responsible for degradation of these components will be overviewed. Degradation of lignin is aerobic and slow; therefore, lignin degradation is a slow step in breakdown of lignocellulosic waste. Microbial production of biogas will be overviewed along with its role in commercial anaerobic digestion for production of biogas from lignocellulosic biomass. Pathways for lignin biodegradation will be described, including delignification by addition of lignin-degrading fungi and bacteria, delignification by lignin-oxidising enzymes and enhancement of biogas formation. The use of metabolic engineering for production of renewable chemicals from lignin degradation will also be described.