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 AfLPMO 8, a novel AA9 family protein derived from Aspergillus fumigatus Z5. AfLPMO 8 demonstrated the ability to bind copper and enhanced its melting temperature ( Tm ) by 17.7 °C. MALDI-TOF-MS analysis revealed that AfLPMO 8 efficiently cleaved phosphoric acid swollen cellulose (PASC) at the C1 and C4 carbons. Additionally, AfLPMO 8 exhibited significant activity on filter paper, effectively dispersing it. When combined with glycoside hydrolases, AfLPMO 8 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 Nc CDH might facilitate electron transfer to the copper ion active center of AfLPMO 8. Ultimately, the identification of AfLPMO 8 might have significant implications for developing novel enzymes for a range of industrial uses, especially in the biofuel and biorefinery sectors.