The production of enzymes of the cellulase complex by the fungus Neurospora
crassa on milled and sieved wheat straw was studied. The effects of straw
concentration, temperature, and initial pH on the production of the beta-gl
ucosidase, exoglucanase, and endoglucanase activities, as well as extracell
ular and mycelial protein, were observed. With an initial pH value of 6.5 a
nd a temperature of 30 degrees C, a straw concentration of 5% yielded the h
igher activities for all the enzymes. Two maxima were observed both for bet
a-glucosidase and endoglucanase, while the exoglucanase activity was consta
nt from the end of the exponential phase. When a protease inhibitor was add
ed, the production of beta-glucosidase was increasing without fluctuations.
When the temperature was 25 degrees C, the enzymes production was lower, w
hereas the mycelial protein value was higher. Changes in the initial pH, lo
wering or raising it, lowered the enzymes production, but favored fungus gr
owth. (C) 1999 Elsevier Science Inc. All rights reserved.