ABSTRACT
Crude oil-based gasoline fuels have been widely used in the transportation sector since the 1920s. However, there have been great public concerns over the adverse environmental and human impact of these fuels. Hence, biomass-based bioethanol fuels have increasingly been used in blending gasoline fuels, in fuel cells, and in biochemical production in a biorefinery context. However, it is necessary to pretreat the biomass to enhance the yield of the bioethanol prior to bioethanol fuel production from feedstocks through the hydrolysis of the biomass and fermentation of the resulting hydrolysates. The USA has been one of the most prolific countries engaged in bioethanol fuel research. US research in the field of bioethanol fuels has intensified in this context in the key research fronts of the production of bioethanol fuels, and to a lesser extent in the utilization and evaluation of bioethanol fuels. For the first research front, pretreatment and hydrolysis of the feedstocks and to a lesser extent fermentation of the feedstock-based hydrolysates and production of bioethanol fuels are the key research areas while for the second research front, direct utilization of bioethanol fuels in fuel cells and bioethanol-based biohydrogen fuels are the key research areas. Research in this field has also intensified for feedstocks of wood biomass, starch feedstock residues, grass, bioethanol fuels, cellulose, lignin, and to a lesser extent starch feedstocks, lignocellulosic biomass at large, and sugar feedstock residues. However, it is essential to develop efficient incentive structures for the primary stakeholders to enhance the research in this field. Although there have been a large number of review papers on bioethanol fuels, there has been no review of the 25 most-cited articles in this field. Thus, this chapter presents a review of these 25 most-cited articles. Then, it discusses the key findings of these highly influential papers and comments on future research priorities in this field.
