The effect of glycerol on the growth, adhesion, and cellulolytic activity of two rumen cellulolytic bacterial species, Ruminococcus flavefaciens and Fibrobacter succinogenes subsp. succinogenes, and of an anaerobic fungal species, Neocallimastix frontalis, was studied. At low concentrations (0.1-1%), glycerol had no effect on the growth, adhesion, and cellulolytic activity of the two bacterial species. However, at a concentration of 5%, it greatly inhibited their growth and cellulolytic activity. Glycerol did not affect the adhesion of bacteria to cellulose. The growth and cellulolytic activity of N. frontalis were inhibited by glycerol, increasingly so at higher concentrations. At a concentration of 5%, glycerol totally inhibited the cellulolytic activity of the fungus. Thus, glycerol can be added to animal feed at low concentrations.

No abstract

Summary ― Two species of rumen fungi, Piromyces (Piromonas) communis FL and Caecomyces (Sphaeromonas) communis FG10, were cultured alone or in association with the cellulolytic bacteria Ruminococcus flavefaciens or Fibrobacter succinogenes on maize stem. A kinetic study of the degradation of the substrate was then made. After 48 h of culture, all non-lignified tissues observed by scanning electron microscopy disappeared with P communis and degradation was as complete as that observed in the rumen. In contrast, C communis degraded little of the plant cell walls. The ability of P communis to more rapidly degrade maize stem was probably due to the presence of filamentous rhizoids. The extent of dry matter loss after 8 days of incubation was practically the same in all the monocultures and in the 4 cocultures. However, the rate of degradation was faster in the bacterial than in the fungal monocultures and the co-cultures.

No abstract