In vitro study of the proteolytic activity of rumen anaerobic fungi

Proteolytic, aminopeptidase, endopeptidase and carboxypeptidase activities of seven strains of rumen anaerobic fungi, selected to represent the fungal population commonly found in the rumen, were investigated in vitro. Whatever the nitrogen source included in the culture medium, a proteolytic activity against the 14C-labelled casein was detected in only one fungal strain. This strain belonged to the genus Piromyces. The activity was extracellular and was found both in the culture supernatant and bound to the mycelium. No carboxypeptidase activity was detected in the seven strains. In contrast, all the strains exhibited aminopeptidase activity. Two strains had an endopeptidase activity.