Process strategies for the transition of 1G to advanced bioethanol production

Nowadays, the transport sector is one of the main sources of greenhouse gas (GHG) emissions and air pollution in cities. The use of renewable energies is therefore imperative to improve the environmental sustainability of this sector. In this regard, biofuels play an important role as they can be blended directly with fossil fuels and used in traditional vehicles’ engines. Bioethanol is the most used biofuel worldwide and can replace gasoline or form different gasoline-ethanol blends. Additionally, it is an important building block to obtain different high added-value compounds (e.g., acetaldehyde, ethylene, 1,3-butadiene, ethyl acetate). Today, bioethanol is mainly produced from food crops (first-generation (1G) biofuels), and a transition to the production of the so-called advanced ethanol (obtained from lignocellulosic feedstocks, non-food crops, or industrial waste and residue streams) is needed to meet sustainability criteria and to have a better GHG balance. This work gives an overview of the current production, use, and regulation rules of bioethanol as a fuel, as well as the advanced processes and the co-products that can be produced together with bioethanol in a biorefinery context. Special attention is given to the opportunities for making a sustainable transition from bioethanol 1G to advanced bioethanol.This research was partially funded by the Regional Government of Madrid (Project SUSTEC-CM S2018/EMT-4348), the Spanish MICIU (Projects RTI2018-96080-B-C22 and ENE2017-85819-C2-2-R), and the European Commission (BIOFIT Project; H2020 Grant agreement 817999). R.M.S. also acknowledges the Spanish MICIU for a “Juan de la Cierva-Incorporación” contract (IJCI-2016-28403).Peer reviewe