Catalytic Oxidative Pretreatment of Woody Biomass At Mild Reaction Conditions and Low Oxidant Loadings

We previously identified that alkaline hydrogen peroxide (AHP) pretreatment catalyzed by copper(II) 2,2΄-bipyridine complexes significantly improves subsequent enzymatic glucose and xylose release from hybrid poplar relative to uncatalyzed AHP pretreatment at modest reaction conditions (room temperature and atmospheric pressure).  This work will present results on several improvements in pretreatment and hydrolysis conditions that result in substantially lower H₂O₂ loadings (35-50 mg/g), lower catalyst concentrations, improved pretreatment rate (less than 10 minutes), and decreased enzyme loadings.  We will report changes both cell wall and solubilized lignin by NMR that suggests oxidative modification on the Cα carbon in the lignin side-chain region, which potentially facilitates Dakin oxidation and subsequent lignin depolymerization. Furthermore, we will present results on the characterization of soluble inhibitors in these hydrolysates and high-throughput screening of Saccharomyces cerevisiae strains for improved tolerance to these inhibitors.