INTERACTIONS BETWEEN FIBROBACTER-SUCCINOGENES, PREVOTELLA-RUMINICOLA,AND RUMINOCOCCUS-FLAVEFACIENS IN THE DIGESTION OF CELLULOSE FROM FORAGES

The synergistic and inhibitory interactions observed between Fibrobact er succinogenes A3c, Prevotella ruminicola H2b, and Ruminococcus flave faciens B34b in the digestion of forage cellulose were studied in deta il. Orchardgrass and alfalfa hays, both at two maturity stages, were u sed as substrates. Sequential inoculation procedures were developed wh ereby a second inoculation was made after the initial fermentation was killed. Total cellulose digestion from sequential addition of the org anisms was then compared to values obtained in simultaneous coculture. When the noncellulolytic P. ruminicola was co-cultured with either of the two cellulolytic species (F. succinogenes or R. flavefaciens) for age cellulose digestion numerically increased over that of the cellulo lytic species alone. In contrast, decreases from co-culture values wer e noted with sequential addition of the organisms. When F. succinogene s and R. flavefaciens were co-cultured, cellulose digestion was reduce d compared to F. succinogenes alone. However, no such reduction was ob served when the organisms were added sequentially. Further experiments indicated that this inhibitory activity is only produced when the org anisms are co-cultured and is stable to autoclaving at 121 degrees C f or 20 min. Inhibition of this type could be the result of bacterocin p roduction by one of the organisms; however, most bacterocins are destr oyed by autoclaving.