Through controlled action on cellulose on the fiber surface, cellulases improve interfiber bonding potential. That enhances paper & board's strength and structure.

The nature of the fiber surface plays a key role in the strength and structure of paper and board. Cellulases modify accessible cellulose on the fiber's surface. This controlled action gives the fiber surface new chemical and structural properties. Cellulases enrich key chemical functional groups and generate fibrillation on the fiber surface. That improves the refinability and strengthening potential of the pulp. 

Mechanical refining may impact the integrity of the entire fiber wall. By contrast, enzymatic modification is a mild treatment that acts on the accessible surface. And unlike chemical strengthening additives, enzymatic treatment unlocks the fiber's own strengthening potential.