Bridging the Gap between Pyrolysis and Fermentation: Improving Anhydrosugar Production from Fast Pyrolysis of Agriculture and Forest Residues by Microwave-Assisted Organosolv Pretreatment

Fast pyrolysis is a potential alternative route to obtain fermentable anhydrosugar (levoglucosan) from biomass. However, the low yield of anhydrosugar from biomass fast pyrolysis hampers its rapid development. Microwave-assisted organosolvolysis could be an effective pretreatment method prior to fast pyrolysis of biomass for addressing this challenge. Here, in order to examine the feedstock flexibility of microwave-assisted organosolv pretreatment on anhydrosugar production from different agricultural and forest residues, three kinds of representative agricultural and forest residues, pine, eucalyptus, and straw, were selected as feedstocks in this study. Pretreatment of them using microwave-assisted glycerolysis was performed in an atmospheric microwave reactor. The pretreated agricultural and forest residues was subsequently fast pyrolyzed in a commercial micropyrolysis reactor. The results demonstrated that microwave-assisted glycerolysis is a versatile and feedstock flexible pretreatment method prior to biomass fast pyrolysis for enhancing anhydrosugar production. The highest yield of levoglucosan (59.4%) was reached by fast pyrolysis of eucalyptus pretreated at 150 W for 20 min. The yield was boosted by 13.5 times compared to that obtained from fast pyrolysis of raw eucalyptus