The mechanism of fiber cutting during enzymatic hydrolysis of wood biomass

► Fiber cutting is observed via fiber length change and microscopy observation. ► Fiber cutting is due to the presence of dislocations. ► Polar light microscopy reveals fibers being cut at dislocations during hydrolysis. ► The number of dislocations of the original fiber and the number of times a fiber is cut is in agreement. ► After fiber cutting no dislocation sites are seen.