Sustainability of sugarcane lignocellulosic biomass pretreatment for the production of bioethanol

[Display omitted] •Technological advances in bagasse pretreatments should met sustainability criteria.•Water, energy and chemicals minimization is crucial for industrial sustainability.•Water reuse from evaporators could reduce water consumption in 2G ethanol production.•The use of green solvents for biomass pretreatment is an incipient, but important, area of research.•Lignin for energy is to be considered in a circular 1G + 2G ethanol production process. The sustainability of a biofuel is severely affected by the technological route of its production. Chemical pretreatment can be considered the traditional method of decomposition of the lignocellulose into its mono and oligomeric units, which can be further bioconverted to ethanol. The evaluation of the recent advances in chemical pretreatments of sugarcane bagasse, especially diluted acids, alkaline, organosolv and ionic liquids, identified the critical points for sustainability. In this context, chemicals recovery and reutilization or their substitution by green solvents, heat and electricity generation through bioenergy, reutilization of water from evaporators, vinasse concentration and the upgrading of lignin were discussed as strategic routes for developing sustainable chemical-based lignocellulose pretreatment. The advances in the technologies that allow greater fractionation of lignocellulosic biomass should be focused on the minimization of the use of natural resources, effluent generation and energy expenditure.