Induction of cellulase in Trichoderma viride as influenced by carbon sources and metals.

Cellulase is an adaptive enzyme in most fungi (Reese and Levinson, 1952), although it is constitutive in cellulolytic bacteria (Hammerstrom et al., 1955). Many polysaccharases are adaptive in fungi, including: pentosanase (Simpson, 1954), polygalacturonase (Phaff, 1947), chitinase (Reynolds, 1954), dextranase (Hultin and Nordstr6m, 1949), and xylanase and mannanase (S0rensen, 1952). Since many of these substrates are insoluble, the question arises as to how an insoluble substrate can induce the formation of an extracellular enzyme. Products of polysaceharide hydrolysis can often induce their respective polysaccharases: galacturonic acid for polygalacturonase in Penicilliurn chrysogenum (Phaff, 1947); xylose for pentosanase in several molds (Simpson, 1954); maltose for amylase in Aspergillus niger (Tanabe and Tonomura, 1953); N-acetylglucosamine for chitinase in Aspergillus fumigatus and Myrothecium verrucaria (Reese, unpublished data). The use of the product as an inducer often leads to lower enzyme yields than are obtained with the substrate. In most cellulolytic fungi tested, however, neither glucose nor cellobiose acted as inducers of cellulase (Reese and Levinson, 1952). Further studies relating to this problem showed that, under certain conditions, some sugars can induce cellulase formation in Trichoderma viride. The present study is a reinvestigation of the induction of cellulase. For comparative purposes, some data on amylase production are also included.