[Anaerobic cellulolytic fungi from cattle rumen].

Two anaerobic fungal strains, Neocallimastix sp. 71 and Piromonas sp. 12, were isolated from cattle rumen. Their motile zoospores have either one (strain 12) or several (strain 71) flagella. The spores get attached to a substrate, germinate and form a branched rhizoid with one sporangium within which a new generation of zoospores appears after 24 h, on the average. Both fungi have a temperature optimum at 39 degrees C and a pH optimum at 6.5-6.7. They can utilize a wide spectrum of mono-, oligo- and polysaccharides. Strain 71 produces acetate, formate, ethanol and lactate while strain 12 forms acetate, formate, lactate and traces of ethanol as main products accumulated upon the fermentation of wheat straw, filter paper and cellobiose in a liquid semidefined medium. Both strains exert the activities of CMCase, Avicelase, cellobiase, amylase and xylanase.