Background: Lytic Polysaccharide Monooxygenases (LPMOs) are auxiliary accessory
enzymes that act synergistically with cellulases and which are increasingly being used in secondgeneration
bioethanol production from biomasses. Several LPMOs have been identified in various
filamentous fungi, including Aspergillus fumigatus. However, many LPMOs have not been characterized
Objective: To report the role of uncharacterized A. fumigatus AfAA9_B LPMO.
Methods: qRT-PCR analysis was employed to analyze the LPMO gene expression profile in different
carbon sources. The gene encoding an AfAA9_B (Afu4g07850) was cloned into the vector pET-
28a(+), expressed in the E. coli strain RosettaTM (DE3) pLysS, and purified by a Ni2+-nitrilotriacetic
(Ni-NTA) agarose resin. To evaluate the specific LPMO activity, the purified protein peroxidase
activity was assessed. The auxiliary LPMO activity was investigated by the synergistic activity in
Celluclast 1.5L enzymatic cocktail.
Results: LPMO was highly induced in complex biomass like sugarcane bagasse (SEB), Avicel®
PH-101, and CM-cellulose. The LPMO gene encoded a protein comprising 250 amino acids, without
a CBM domain. After protein purification, the AfAA9_B molecular mass estimated by SDSPAGE
was 35 kDa. The purified protein specific peroxidase activity was 8.33 ± 1.9 U g-1. Upon
addition to Celluclast 1.5L, Avicel® PH-101 and SEB hydrolysis increased by 18% and 22%, respectively.
Conclusion: A. fumigatus LPMO is a promising candidate to enhance the currently available enzymatic
cocktail and can therefore be used in second-generation ethanol production.