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The adsorption of cellulase on cellulose and a lignacious residue was examined by using cellulase from Trichoderma reesei, hardwood pretreated by dilute sulfuric acid under high pressure, and a lignacious residue prepared by a complete enzymatic hydrolysis of the pretreated wood. A significant amount of cellulase was found to adsorb on the lignacious residue during the hydrolysis of the pretreated wood. Hence, the adsorption of enzyme on the lignacious residue as well as cellulose must be taken into account in the development of the hydrolysis kinetics. It was found that the adsorption of enzyme on cellulose and on the lignacious residue could be represented by Langmuir type isotherms. The data show that the pretreatment at a higher temperature results in more enzyme adsorption on the cellulose fraction and less on the lignacious residue fraction. The relationship between the hydrolysis rate and the amount of enzyme adsorbed is discussed.

SummaryPartial acid hydrolysis was studied as a pretreatment to enhance enzymatic hydrolysis. Such a pretreatment Gas carried out in a continuous flow reactor on oak, corn stover, newsprint, and Solka Floc at temperatures ranging from 160 to 220°C, acid concentrations ranging from 0 to 1.2%, and a fixed treatment time of 0.22 min. The resulting slurries and solids were then hydrolyzed with Trichoderma reesei QM 9414 cellulase at 50°C for 48 hr. For all substrates except Solka Floc, increased glucose yields were achieved during enzymatic hydrolysis of the pretreated materials as compared to hydrolysis of the original substrates. In several cases, after pretreatment, 100% of the potential glucose content of the substrate was converted to glucose after 24 hr of enzymatic hydrolysis. It is felt that the increased glucose yields achieved after this pretreatment are due to the acid's removal of hemicellulose, reduced degree of polymerization, and possibly due to a change in the crystal structure of the cellulose.

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