The inhibition of fungal cellulolysis by cell-free preparations from ruminococci

The degradation of filter paper by the anaerobic fungus Neocallimastix frontalis strain RE1 was reduced by the addition of cell-free supernates from cultures of Ruminococcus albus strain J6 and R. flavefaciens strains 17 and 007. Fungal uptake of, and growth on, glucose was not affected. After gel permeation and anion exchange chromatography, inhibitory activity towards fungal cellulolysis was recovered in a fraction from strain 17 that contained at least five negatively charged polypeptide components, molecular mass 45-68 kDa, on SDS-PAGE.