Elucidating the role of AfLPMO8 from Aspergillus fumigatus Z5 in cellulose oxidative degradation: mechanistic insights into a lytic polysaccharide monooxygenase.

The potential applications of lytic polysaccharide monooxygenases (LPMOs) in biomass degradation have garnered significant interest. In this study, we characterized AfLPMO8, a novel AA9 family protein derived from Aspergillus fumigatus Z5. AfLPMO8 demonstrated the ability to bind copper and enhanced its melting temperature (Tm) by 17.7 °C. MALDI-TOF-MS analysis revealed that AfLPMO8 efficiently cleaved phosphoric acid swollen cellulose (PASC) at the C1 and C4 carbons. Additionally, AfLPMO8 exhibited significant activity on filter paper, effectively dispersing it. When combined with glycoside hydrolases, AfLPMO8 markedly improved the hydrolysis efficiency of various agricultural residues, such as corn, rice, soybean, and wheat straw. Furthermore, GRAMM docking analysis showed that Tyr51 in NcCDH might facilitate electron transfer to the copper ion active center of AfLPMO8. Ultimately, the identification of AfLPMO8 might have significant implications for developing novel enzymes for a range of industrial uses, especially in the biofuel and biorefinery sectors.