Energy Assessment of Second-Generation (2G) Bioethanol Production from Sweet Sorghum (Sorghum bicolor (L.) Moench) Bagasse

Sweet sorghum bagasse (SSB) provides a raw material rich in polysaccharides that can be converted into biofuel and other high-value-added bioproducts under the biorefinery concept. The aim of this study was to evaluate the effect of hydrothermal pretreatment on the availability of SSB fermentable sugars for bioethanol production, considering the energy balance of the process. For this, the biomass was subjected to one process, pre-saccharification simultaneous and fermentation (PSSF). Previously, the temperature, time, and particle size effect were determined, as well as the enzymatic load for the more significant release of monomeric sugars. It was observed that the increase in the pretreatment severity, defined by the severity factor [log(Ro)], resulted in a more significant release of sugar and energy consumption. In the PSSF, bioethanol production was 22.17 g/L, with a total energy consumption of 2.46 MJ/g of processed biomass, of which 79.14% was by concept of electricity.