Technical Developments for Vegetable Waste Biomass Degradation by Thermophiles

Environmental concerns such as greenhouse gas emission and fossil fuels depletion, have driven increasing technological and economical interest in the study of biorefining processes in order to convert organic waste materials (biomass) into bioethanol, biodiesel, building blocks (chemicals) and biomaterials. Vegetable waste biomass is produced continuously at global level by agro-industries, agriculture and forestry and according to its origin, it can be distinguished in three main groups i.e.: food wastes, crop residues and forestry/wood residues. Plant biomass and vegetable industrial wastes such as lignocellulosic biomass is object of great interest since it can be hydrolysed to have starch, (hemi)cellulose and lignin that in turn will be converted in value added chemicals and/or biofuels. Pre-treatment steps using physico-chemical or enzymatic processes, make the conversion of lignocellulosic biomass into biofuels more expensive than the extraction of fossil fuels. This chapter underlines the capability of thermophiles and of their enzymes to bypass the problems and limits linked with the lignocellulosic biomass use. Studies concerning the exploitation of agro-waste as growth medium for the production of biotechnologically useful extremophilic microorganisms and their relative enzymes, the pre-treatment and digestion of lignocellulosic fractions in order to obtain mono- and oligosaccharides, the use of thermophilic enzymes in comparison to that of commercial, for a convenient set up of a total degrading process, the chemical procedures for the characterization of new compounds obtained from lignocellulosic materials, are also discussed. Moreover, the opportunity to employ thermophiles in the conversion of lignocellulosic materials into ethanol using only one step process, are also provided.