CELLULOSE MORPHOLOGY AND ENZYMATIC REACTIVITY - A MODIFIED SOLUTE EXCLUSION TECHNIQUE

An expeditious and accurate simplification of Stone and Scallan's solu te exclusion technique was developed, thereby avoiding several sources of experimental error coupled with the determination of cellulose por e volume. Using this method, it is shown that cellulolytic enzymes do not enter into the micropores of five studied celluloses. These result s suggest that hydrolysis occurs initially at the external surface of the fibers. This surface area was calculated with the help of adsorpti on isotherms of bovine serum albumin. The obtained values for the diff erent samples agree with the microscopically observed cellulose morpho logy. The correlation obtained by several authors relating cellulose p orosity and its digestibility is explained as a consequence of the low er crystallinity and easier fragmentation of the more porous cellulose s during hydrolysis. (C) 1994 John Wiley and Sons, Inc.