Addition of metal ions to a (hemi)cellulolytic enzymatic cocktail produced in-house improves its activity, thermostability, and efficiency in the saccharification of pretreated sugarcane bagasse

• Inexpensive metal ions reduce non-productive adsorption of enzymes onto lignin.
• Mn2+ provided the best (hemi)cellulolytic activity and stability.
• Saccharification of acid-pretreated bagasse with Mn2+ increased 34% glucose release.

High activity and stability are essential for (hemi)cellulolytic enzymes used in biomass conversion, while non-productive binding of cellulases to lignin reduces saccharification efficiency and needs to be avoided. One potential strategy is the addition of inexpensive metal ions. This paper describes the influence of divalent metal ions on the activity, thermostability, and saccharification efficiency of (hemi)cellulolytic enzymes produced in-house by Aspergillus niger under solid-state fermentation (SSF). The use of Mn2+ provided the best (hemi)cellulolytic activity and stability, with an increase in endoglucanase activity of up to 57%. The use of Mn2+ was then investigated in the saccharification of sugarcane bagasse submitted to acid, steam-explosion, and hydrothermal pretreatments. The addition of Mn2+ ions at 10 mM in the saccharification of acid-pretreated bagasse resulted in a 34% increase in glucose release. These positive effects appeared to be due to a reduction in non-productive enzyme adsorption. The findings suggest that the addition of inexpensive metal ions can help to improve activity, thermostability, and saccharification efficiency of (hemi)cellulolytic enzymes.