Effect of cellobiose, glucose, ethanol, and metal ions on the cellulase enzyme complex of Thermomonospora fusca

Abstract

The saccharification of cellulosic substrates by cellulase from Thermomonospora fusca, strain YX, was influenced by the presence of various substances. Cellobiose was strongly inhibitory, reducing the activity against swollen cellulose to 25% at 5% concentration. Glucose had much less effect, reducing activity to 40% at 20% concentration. Ethanol was found to be only slightly inhibitory to the cellulase, reducing activity by about 15% at 6% concentration, but much more inhibitory to the cell-bound β-glucosidase activity. Of the numerous metal ions examined, Ca²⁺ and Co²⁺ at 0.1mM-1.0mM concentration were found to be slightly activating under assay conditions, while 1.0mM Pb²⁺ and Hg²⁺ were the most inhibitory ions. The implications of these results for the design of commercial processes for ethanol production from cellulose are discussed.