Comparative analysis of two recombinant LPMOs from Aspergillus fumigatus and their effects on sugarcane bagasse saccharification

• Published in: Enzyme and microbial technology 2021-03, Vol.144, p.109746-109746, Article 109746
• Main Authors: Velasco, Josman, de Oliveira Arnoldi Pellegrini, Vanessa, Sepulchro, Ana Gabriela Veiga, Kadowaki, Marco Antonio Seiki, Santo, Melissa Cristina Espirito, Polikarpov, Igor, Segato, Fernando
• Format: Article
• Language: English
• Subjects: Aspergillus; Cazymes; Enzymatic saccharification; LPMOs; Lytic polysaccharide monooxygenases; Sugarcane bagasse; Thermophiles
• ISSN: 0141-0229; 1879-0909
• DOI: 10.1016/j.enzmictec.2021.109746

[Display omitted] •Oxidative enzymes were successfully expressed in heterologous system.•Two AA9 lytic polysaccharide monooxygenases from A. fumigatus were biochemically characterized.•The regioselectivity and biochemical properties were elucidated.•Collaborative effect of AA9 with cellulases in lignocellulosic biomass saccharification was demonstrated. Lytic polysaccharide monooxygenases (LPMOs) have been introduced into industrial cocktails used for biomass saccharification due to their capacity to boost enzymatic conversion of recalcitrant cellulose. The genome of the thermotolerant ascomycete Aspergillus fumigatus encodes 7 genes for LPMOs that belong to auxiliary activity family 9 (AA9). Here, we cloned, successfully expressed and performed biochemical evaluation of two CBM-less A. fumigatus LPMOs (AfAA9A and AfAA9B). A high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) analysis demonstrated that AfAA9A and AfAA9B are able to oxide cellulose at C1 and C1/C4 positions, respectively. Synergic effects of LPMOs (separately and in combination) with cellulases were investigated. Supplementation of Celluclast 1.5 L with a low concentration of AfAA9B improved in 20 % the saccharification of sugarcane bagasse pretreated by steam explosion (SEB), while AfAA9A did not improvethe saccharification. Analysis of the hydrolyzed biomass by confocal laser scanning microscopy (CLSM) showed the LPMOs are promoting lignin oxidation in the lignocellulosic material. This study complements the available results concerning the utilization of LPMOs in the enzymatic saccharification of lignocellulosic biomass.