Crude glycerol organosolv pretreatment: Chain integration for the production of 2G ethanol and biogas

Abstract

The pretreatment of sugarcane bagasse with crude glycerol from biodiesel production was evaluated at three different times, varying the temperature, glycerol, and solids concentrations. The pretreatment efficiency was evaluated based on the results of enzymatic hydrolysis, and subsequently, the hydrolysate was fermented to ethanol. Furthermore, the pretreatment liquor was used for biogas production. The results have shown that the pretreatment time is not statistically significant in the enzymatic hydrolysis step. The highest glucose concentration (80.7 g.L−1) was obtained for the most severe pretreatment condition: 210 °C, 70 % glycerol, and 30 % solids. The fermentation of the resulting hydrolysate led to a yield of 80.23 % in ethanol fermentation, and the pretreatment liquor produced 814.56 NmLCH4.g−1VS in anaerobic digestion. This work has shown the efficiency of pretreatment with crude glycerol, an alternative for the integrated production of second-generation ethanol and biogas using a biodiesel subproduct, in a biorefinery concept.