Microbial Ways for Pretreatment of Lignocellulosic Waste

Bioenergy is one of the most promising renewable energy resources, derived from biofuels, which are produced by the bioconversion of various types of biomass, such as organic fractions of municipal solid waste, sludge from effluent treatment plants, kitchen waste, agricultural lignocellulosic waste, etc. Lignocellulosic biomass (LCB) is a cheap and abundantly available second-generation biomass source for the production of biofuels. The lignocellulosic biomass cannot be utilized efficiently due to its recalcitrance because of various factors. In order to overcome this problem, the biomass should be pretreated before bioconversion. Chemical and physical methods that are commonly employed for the pretreatment have certain drawbacks, such as reduced energy efficiency, environmental hazards, etc. To overcome these drawbacks, biological treatment approaches such as the use of live or dead microbial cells, fungi, bacterial consortia, microbial cell-free extracts, and purified enzymes can be used. The present chapter discusses microbial pretreatment approaches for the pretreatment of lignocellulosic biomass for biofuel production and their underlying mechanisms. It reviews various cellulolytic and lignolytic microorganisms and enzymes used for biomass pretreatment, ways of employing these microorganisms, and the efficiency of these methods in terms of energy balance and cost. The article also reviews the scale at which these technologies are being studied worldwide.