Characterization of a rare trifunctional xylanase from endophytic fungus Chaetomium globosum and its synergistic effect with cellulase cocktail

Multifunctional xylanases present considerable potential across various sectors, including the food, chemical and biorefinery industries. Herein, a novel trifunctional xylanase Xyn1.28, identified from the lignocellulose-degrading endophytic fungus Chaetomium globosum DX-THS3, exhibits high xylanase activity (230.37 ± 2.69 U/mg) along with notable endo -glucanase activity and rare arabinofuranosidase activity, which accounted for 17–33 % and 43 % of the xylanase activity, respectively. When combined with commercial cellulase cocktail Celic CTec2 at a 1:10 activity ratio, a significant synergistic effect enhanced sugar release by 27.5 % during unpretreated corn straw degradation. Alkali-treated corn cob degradation efficiency was also improved, reducing the time to achieve maximum sugar yield by 12 h. The sugar release profiles during the initial degradation stages indicated that Xyn1.28 plays a crucial role in the initial stages of hydrolyzing biomass. Furthermore, molecular docking analysis indicated that the unique site GLN-74 may significantly influence the arabinofuranosidase activity of Xyn1.28 by forming a hydrogen bond with HIS-108. Experiments involving the mutated GLN-74 further confirmed the critical role of this site in the arabinofuranosidase activity of Xyn1.28. Overall, this rare multifunctional endo -xylanase is well-positioned to facilitate the development of efficient lignocellulose degradation systems and advance cost-effective biomass conversion.