Assessment of methods to determine minimal cellulase concentrations for efficient hydrolysis of cellulose

The enzyme loading needed to achieve substrate saturation appeared to be the most economical enzyme concentration to use for hydrolysis, based on percentage hydrolysis. Saturation was reached at 25 filter paper units per gram substrate on Solka Floc BW300, as determined by studying (a) initial adsorption of the cellulase preparation onto the substrate, (b) an actual hydrolysis or (c) a combined hydrolysis and fermentation (CHF) process. Initial adsorption of the cellulases onto the substrate can be used to determine the minimal cellulase requirements for efficient hydrolysis since enzymes initially adsorbed to the substrate have a strong role in governing the overall reaction. Trichoderma harzianum E58 produces high levels of beta-glucosidase and is able to cause high conversion of Solka Floc BW300 to glucose without the need for exogenous beta-glucosidase. End-product inhibition of the cellulase and beta-glucosidase can be more effectively reduced by employing a CHF process than by supplemental beta-glucosidase.