Kinetics of cellulose saccharification by Trichoderma reesei cellulases

In order to optimize the enzymatic hydrolysis of three celluloses (carboxym ethyl cellulose, powdered cellulose and microgranular cellulose), the effec t of varying enzyme and substrate concentration, temperature and pH was stu died. The best experimental conditions found to degrade the celluloses were 48 h of incubation, an enzyme concentration of 7 U ml(-1) for the cellulas es and 0.1 U ml(-1) for the beta -glucosidase (from A. niger) and a substra te concentration of 0.5%. Under these conditions, carboxymethyl, powdered a nd microgranular celluloses were degraded 11.2, 40.2 and 15.8%, respectivel y. Results suggested that cellulases induced in the presence of each substr ate were able to hydrolyze more effectively, if substrate concentration was similar to that used in the induction of enzymes. The rate of saccharifica tion of Sigmacell 100 at high substrate concentrations was 93% lower than t he maximum rate observed with 0.5% cellulose. Differences in the degree of substrate inhibition when using different substrates were particularly rele vant to the experimental design of comparative studies. (C) 2001 Elsevier S cience Ltd. All rights reserved.