Biochemical conversion of biomass to fuels

Abstract

Biomass can provide both hydrocarbon fuels and chemical compounds such as alcohols, gums, sugars, lipid-based products, etc. Biomass-derived fuels have acquired a lot of attention during recent years because of the abundance of supply of resources and lower green house gas emissions. Grasses, agricultural residues, animal residues and waste, used oils, etc., can be used as starting materials in the production of biofuels. Ethanol and biodiesel have found greatest application and contribute significantly to fuels. However there is growing interest in other alternatives: Hydrogen, methane, butanol, renewable diesel, and petroleum compatible fuels from advanced catalytic biotech processes. Characteristics of various feedstocks and fuels, processes for conversion of biomass to biofuels, the physical, chemical factors and limitations effecting the conversion of biomass to fuels are discussed in this chapter. Process parameters include pH, temperature, and residence time. Additionally, chemical parameters include carbon source, nutrients, acid and alkaline hydrolysis agents, and phenolic inhibitors and sugars generated within the process. Several limitations to bioconversion of biomass are described such as size reduction, crystallinity, by-product inhibition to fermentation, deactivation of cellulases, ethanol tolerance by yeast, and co-fermentation of various sugars. Recent innovations and future developments in recombinant DNA technology and protein engineering are aimed at overcoming limitations to bioconversion. Understanding the limitations and applying suitable biotechnological applications will support future developments for producing biofuels.