Enhanced Enzymatic Hydrolysis of High-Solids Content Corncobs by a Lytic Polysaccharide Monooxygenase from Podospora anserina S Mat⁺ for Valuable Monosaccharides

Abstract

Lytic polysaccharide monooxygenase (LPMO) has been found to enhance cellulase activity and promote efficient utilization of corncob cellulose. To this end, a novel LPMO from Podospora anserina S mat+ (PaLPMO) through in silico screening was heterologously expressed in Escherichia coli BL21(DE3) and its biochemical properties were investigated. To reduce production costs, chaperones and site-directed mutagenesis were employed to enhance the protein's solubility, yielding an 8% increase. Through single-factor experiments, the optimal hydrolysis condition for the highest glucose yield of 129.8 g/L was identified as 25% highsolids content of corncob at 60 °C and pH 5.5 using a PaLPMO-to-cellulase ratio of 1:3 (total protein concentration of 12 mg/g) and with the addition of 0.5 mmol/L Mn 2+ . This result represented a 24% improvement compared to cellulase alone and a 33% reduction in commercial cellulase usage with the same degree of hydrolysis. The hydrolysis products of high-solids content corncob degradation were further used to produce valuable D-allulose through glucose isomerase and Dallulose 3-epimerase catalysis in a ratio of 2:1, with a yield of 56.22 g/L fructose and 20.6 g/L D-allulose. The PaLPMO and cellulase complex significantly improved the degradation efficiency of corncob residue and reduced cellulase usage in lowering the production cost. These findings contribute to developing comprehensive corncob utilization and pave the way for sustainable and efficient energy and resource utilization.

Implementation of CDH in LPMO-Containing Minimal Cellulase Cocktails to Tune Bioproduct Production from Lignocellulosic Biomass

“…Nevertheless, in a recent study, Cai and colleagues have shown that an AA9 from P. anserina (enzyme ID not reported) could enhance the absolute glucose extraction yield on corncobs by up to 24% (using 8 mg/g of industrial Cellic CTec3 cocktail and 4 mg/g of LPMO) . Although it is possible that the boost observed in this study directly originates from the action of the tested Pa AA9, it is also likely that this LPMO could act as a H 2 O 2 supplier for the AA9s potentially present in the Cellic CTec3 cocktail (3 AA9s are encoded in the genome of T.…”