Chimeric cellulases (CD- CBM) show greater penetration and bulk degradation of amorphous cellulose films at room temperature. Cellulose volume profiles are shown for each cellulase. Amorphous cellulose films were incubated at room temperature with a) Cel9A or Cel9A-CBM, and b) Cel5A or Cel5A-CBM. Plots show the normalized cellulose volume fraction versus normalized distance from the silicon oxide surface. Due to variance in film preparation the baseline (film prior to enzyme addition) for every cellulose film assay is shown. Arrows indicate the cellulose-buffer interface. Brown dotted line shows the extrapolation of the cellulose profile for Cel9A-CBM after the enzyme layer at the surface of the film was removed.