(731e) Comparison of Celf, Cu-AHP, and HS Ionic Liquid Pretreatment of Hardwoods: Hydrolysis Yields, Comprehensive Mass Balances, and Lignin Properties

In this work, three pretreatments under investigation at the DOE Bioenergy Research Centers (BRCs) are subjected to a side-by-side comparison to assess their performance on model bioenergy hardwoods. These will include co-solvent enhanced lignocellulosic fractionation (CELF), high-solid loading pretreatment with ionic liquid (HS-IL), and Cu-catalyzed alkaline hydrogen peroxide pretreatment (Cu-AHP). The pretreatments will be individually optimized for the feedstock and common performance metrics as assessed by a single lab will be used as a basis of comparison. The first component of this will be to assess the susceptibility of the pretreated biomass to hydrolysis by cellulolytic enzymes. This reactivity will be related to both structural and compositional changes to plant cell wall as a consequence of pretreatment. The second component will be to determine comprehensive mass balances on the pretreatments. This will include assessing the solubilization, depolymerizaiton, and conversion of cell wall biopolymers as well as the solvent requirements, their degradation, and their potential for reuse. An important feature of the pretreatments in this study is that all three have shown preliminary evidence of yielding lignins with properties amenable to further valorization. As the final component of this work, we will characterize the yields, structural properties, and reactivity of the soluble and insoluble lignin fractions generated by these pretreatments.