We have attempted to understand the mechanisms of indigo backstaining
during enzyme stone washing by separately analyzing dye staining level
s on different cotton surfaces during the process. The high ability of
the cellulase enzyme protein to bind to cotton cellulose is the major
cause of backstaining. Further studies of commercial cellulases show
that the pH of maximum cellulase activity may not be the same pH of ma
ximum of cellulase binding capacity to the substrate, and also that in
digo dyes have completely different affinities for cellulase proteins
from different fungal origins.