Scale-up and process integration of sugar production by acidolysis of single and mixed feedstocks in ionic liquids

Lignocellulosic biorefineries have tonnage and throughput requirements that must be met year round and there is no single feedstock available in any given region that is capable of meeting the price and availability demands of the biorefineries scheduled for deployment. Ionic liquid (IL) pretreatment with certain ILs is receiving significant attention as a potential process that enables fractionation of a wide range of feedstocks. Acid catalysts have been used previously to hydrolyze polysaccharides into fermentable sugars during IL pretreatment, which could potentially provide a means of liberating fermentable sugars from lignocellulose without the use of costly enzymes. However, successful optimization and scale-up of the one pot acid-assisted IL deconstruction for further commercialization involves challenges such as reactor compatibility, mixing at high solid loading, sugar recovery, IL recycling, etc., which have not been effectively resolved during the development stages at bench scale. Here we present the successful scale-up demonstration of the acid-assisted IL deconstruction on single herbaceous feedstock as well as feedstock blends of municipal solid wastes and agricultural residues by 30-fold, relative to the bench scale (6L vs 0.2L), at 10, 15 and 20% solid loading. By integrating IL pretreatment and acid hydrolysis with subsequent centrifugation and extraction, the sugar and lignin products can be further recovered efficiently. This scale-up development at Advanced Biofuels/Bioproducts Process Demonstration Unit (ABPDU) will leverage the opportunity and synergistic efforts towards developing a cost-effective IL based deconstruction technology by drastically eliminating enzyme and reducing water usage, and simplifying the downstream sugar/lignin recovery and IL recycling.