Experimentelle Untersuchungen zur Produktion und Aktivität cellulolytischer Enzyme bei höheren Pilzen aus dem Meer- und Brackwasser

Abstract

Twenty isolations of marine higher fungi were examined in regard to their cellulolytic capabilities. Application of the viscosimetric method produced detailed information on the cellulolytic activities of marine fungi. However, only the C_x-component of the total cellulase-complex could be estimated by this method. The most active species were Dendryphiella salina, Chaetomium ramipilosum, Asteromyces cruciatus and Humicola alopallonella. Only very slight or no C_x-activity was observed in Cirrenalia macrocephala, Monodictys pelagica and Zalerion maritimum. This finding reveals no correlation between the cellulolytic activity of the fungi in vitro and their frequency on wood-substrates in situ. For example, differences in the intensity of C_x-cellulase production of D. salina are caused by variations in salinity and composition of the nutrient broth, especially by the kind of cellulose added for enzyme induction and by the addition or absence of glucose. Most of the C_x-cellulase produced is present in the cell-free culture-filtrate. Only a small quantity is absorbed by the cellulose particles or the fungal mycelia. Parallel to the mycelial growth, and accompanied by a shift in pH, the C_x-cellulase-activity rises continuously, attaining a maximum after several weeks. During further cultivation, the maximum remains more or less constant for a long period. Tests using different methods, e.g. cellulose-powder-agarplates, proved unsuitable because of spreading hyphal growth, dark pigmentation, heavy sexual or asexual sporulation and relatively low cellulase production during short culture periods.