Bioethanol production from cereal crops and lignocelluloses rich agro-residues: prospects and challenges

The existing energy demand, fluctuating oil prices and repercussions due to usage of fossil fuels have enhanced the requirement for alternative energy sources. Bioethanol derived from cereal crops serve as a promising alternative to conventional gasoline owing to the advantages of feedstock availability, reduction in production costs coupled with significant low greenhouse gas emissions. Recent studies focused on agro-residues derived from cereal crops had illustrated potential technical advantages for bioethanol production. Conventional bioethanol process includes pretreatment, saccharification and fermentation. Unlike acid and base pretreatment methods, enzymatic and ionic liquid pretreatment methods showed promising results in delignification process. Besides, studies demonstrated that integrated processes like simultaneous saccharification and fermentation and consolidated bioprocessing showed significant reducing sugar release and higher bioethanol yield from cereal crops and their residues. Moreover, deploying advanced technologies such as genome editing and metabolic engineering techniques could not only enhance bioethanol content but also helps in development of biorefinery theme, which leads to development of inexpensive technology. These studies and know-how technologies imply that the cereal crops and their residues could be viable substrates for bioethanol production that ultimately bolster the energy security.