An innovative approach of priming lignocellulosics with lytic polysaccharide mono-oxygenases prior to saccharification with glycosyl hydrolases can economize second generation ethanol process.

Abstract Two Lytic polysaccharide Mono-Oxygenases (LPMOs), non-modular (PMO_08942) and modular (PMO_07920), from thermotolerant fungus Aspergillus terreus 9DR cloned and expressed in Pichia pastoris X33 and purified to homogeneity using ion-exchange chromatography were found to be of ∼29 and ∼40 kDa, respectively. Both LPMOs were optimally active at 50° C; PMO_08942 was active under acidic condition (pH 5.0) and PMO_07920 at pH 7.0. Modular LPMO (PMO_07920) tethered to CBM-1 was found to be versatile as it showed appreciable activity on complex polysaccharide (both cellulose and xylans) as compared to non-modular (PMO_08942). The t1/2 of PMO_08942 (∼192 h, pH 5.0) and PMO_0792 (∼192 h, pH 7.0) at 50° C, suggests highly stable nature of these LPMOs. Fluorescently tagged modular AA9 was studied microscopically to understand interaction with pretreated biomass. Priming of biomass for up to 6 h with LPMOs prior to initiating hydrolysis with core cellulase enzyme resulted in significantly higher saccharification.