Recent trends in valorization of lignocellulose to biofuel

Abstract

Bioconversion of renewable lignocellulosic biomass is globally gaining significant prominence. Market forces demonstrate a drive towards products benign to natural environment increasing the importance of renewable materials. The development of second generation bioethanol from lignocellulosic biomass serves many advantages from both energy and environmental point of views. Lignocellulose is a major structural component of woody and non-woody plants and consists of cellulose, hemicellulose and lignin. The effective utilization of all the three components would play a significant role in the economic viability of cellulosic ethanol. The huge amount of plant biomass can be used as an inexpensive feedstock for the production of various value added products including biofuels, chemicals and improved animal feeds. Biomass conversion process involves five major steps: choice of suitable biomass, effective pretreatment, production of saccharolytic enzymes such as cellulases and hemicellulases along with the accessory enzymes, fermentation of hexoses and pentoses, downstream processing. Within the context of production of fuels from biomass, pretreatment has come to denote processes by which cellulosic biomass is made amenable to the action of hydrolytic enzymes. The limited effectiveness of current enzymatic process on lignocellulose is thought to be due to the relative difficulty of pretreating the feedstocks. The present chapter is a comprehensive state of the art describing the advancement in recent pretreaments, metabolic engineering approaches, valorization with special emphasis on the latest developments in consolidated biomass processing and biorefinery concept for the production of biofuel.