Effective fractionation of <i>Eucalyptus globulus</i> bark by acetone‐based organosolv

Abstract Eucalyptus globulus bark is a lignocellulosic byproduct from the pulp industry, traditionally used for energy production, with potential for biorefining and valorization. An effective pretreatment process is required for successful fractionation of major components of biomass (lignin, hemicellulose, and cellulose). Choosing the pretreatment step is a major challenge in the development of lignocellulosic biorefineries. In this work, E. globulus bark was pretreated and fractionated using the acetone‐based organosolv process. A Doehlert experimental design was used to evaluate the effects of time (60–180 min) and temperature (180–230 °C) of organosolv pretreatment on the fractionation of the main components and the enzymatic digestibility of cellulose. The results show that a noncatalyzed acetone organosolv process is suitable for the fractionation and valorization of E. globulus bark. Effective delignification, hemicellulose removal, and cellulose recovery and digestibility were achieved with a wide range of experimental conditions. Under the optimal organosolv conditions (60 min at 198 °C) a cellulose‐to‐glucose conversion of 95% was achieved after enzymatic hydrolysis, representing a production of 46 g of glucose per 100 g of bark. A considerable amount of lignin (&gt;65%) can be recovered from the organosolv liquid stream obtained using the optimal conditions (15 g per 100 g of bark). In conclusion, a noncatalyzed acetone‐based organosolv process effectively fractionates E. globulus bark and the pretreatment conditions can be adjusted to maximize both solid recovery and the enzymatic conversion of cellulose.