Deep Eutectic Solvents: Effect of Pre-treatment of Biomass to Enzymatic Digestion

Abstract

As the demand for greener fuel sources increases, renewable fuel sources are being studied. Biofuels obtained from cellulosic sugars in biomass sources are one such alternative fuel source. Due to the properties of cellulose and lignin in biomass, pre-treatment methods need to be conducted to assess the enzymatic access to cellulose. This study used deep eutectic solvents (DES) as a pre-treatment strategy to weaken the intermolecular forces between cellulose and lignin. DESs are prepared by mixing a solid state hydrogen bond donor and a solid state hydrogen bond acceptor yielding a liquid. Three DESs were synthesized with choline chloride serving as the hydrogen bond acceptor for each and urea, trifluoroacetamide, and oxalic acid serving as hydrogen bond donors. The biomass source, corn stover from Zea mays, was then incubated with each DES. Of the three synthesized DESs, the urea-choline chloride DES produced the best results when incubated with cellulase enzyme. Since the urea-choline chloride DES produced the most significant deconstruction, the DES was recycled and reused three more times to test its ability for reuse in subsequent incubations with fresh biomass.