chapter  16
12 Pages

Enzymes

Key Role in the Conversion of Waste to Bioethanol
WithAbhijeet Thakur, Kedar Sharma, Kaustubh C. Khaire, Vijay S. Moholkar, Arun Goyal

The world is currently facing two major challenges, the resource scarcity and overproduction of waste. Due to the uneven distribution and excess consumption of resources, the demand for energy is high and increasing day by day. On the other hand, the mounting of waste needs strategic waste management. In the environment, microbes present utilize organic waste by releasing enzymes, but the rate of degradation is much slower than the production of waste. Organic waste majorly constitutes agricultural waste or municipal solid waste that can be converted to bioenergy (methane, methanol, bioethanol and biobutanol). Cellulose and hemicellulose portion of the solid wastes are hydrolyzed by cellulases and hemicellulases into fermentable sugars like glucose, xylose and arabinose. Fermenting microbes further utilize these sugars for the production of bioethanol, and residual biomass used as compost in the agricultural field. Ethanol produced from cellulose and hemicellulose is environmental friendly fuel as it emits lower carbon monoxide. An overview of breakdown of cellulosic and hemicellulosic polysaccharides present in agro-waste and production of bioethanol with focus on recent developments is described.