(35e) Inexpensive pH Matched Acid–Base Conjugate Ionic Liquids for One-Pot Pretreatment and Saccharification of Lignocellulosic Biomass
Due to its abundance and global availability, non-food sustainable lignocellulosic biomass is a promising feedstock for commercial scale production of biofuels and renewable chemicals. The efficient and affordable conversion of lignocellulosic biomass into these products is currently hindered by its recalcitrant nature. Ionic liquid (IL) based pretreatment technologies are showing promise in meeting the desired key characteristics of biomass pretreatment. Despite the effectiveness of [C2C1Im][OAc] and similar ILs at reducing the recalcitrance of lignocellulosic biomass, the inhibition of enzyme activity and microbial toxicity of these top performing ILs often require extensive water washes to remove residual IL from pretreated biomass prior to enzymatic hydrolysis. To overcome the pH mismatch and cytotoxicity issues with commercially available enzyme mixtures, we screened ILs for desired pH and biocompatibility, and employed cheap acid-base conjugate ionic liquids to develop an integrated one-pot pretreatment and saccharification process. High fermentable sugar yields are achieved in the presence of commercial enzyme without pH adjustment and washing operation after pretreatment of biomass. This approach aims to resolve several of the most significant obstacles towards the realization of an efficient, integrated, affordable and scalable IL conversion technology suitable for deployment at a biorefinery and opens the door to a new approach to biomass conversion into renewable biofuels and chemicals.