ABSTRACT
Anaerobic fungi have been isolated mainly from the rumen of cattle and sheep, but there are also isolates from the cecum of the horse, and the organisms have been shown to be present in the guts of feral ruminants and marsupials. Evidence that the products are inhibitors has been obtained from studies on cellulolysis and xylanolysis by fungi in the presence and absence of lactate-utilizing rumen organisms, in which it was demonstrated that degradation was increased in the cocultures, and from studies on the growth of fungal monocultures in product-supplemented media. The suggestion that anaerobic fungi produce hemicellulases arose from studies by a number of workers who observed degradation of straw and leaf tissue by the organisms. Probably the major regulatory influences on carbohydrate fermentation by anaerobic fungi in the rumen are due to the levels of fermentation end products, and the low partial pressure of H2 in this ecosystem would most likely be the major influence.
