ARS | Publication request: COMPETITION AMONG THREE STRAINS OF RUMINAL CELLULOLYTIC BACTERIA IN CONTINUOUS CULTURE

Submitted to: Conference on Rumen Function
Publication Type: Abstract Only
Publication Acceptance Date: November 11, 1997
Publication Date: N/A

Technical Abstract: Strains of three predominant species of ruminal cellulolytic bacteria -- Fibrobacter succinogenes S85, Ruminococcus flavefaciens FD-1, and Ruminococcus albus 7 -- were grown in triculture in cellulose- limited chemostats at dilution rates of 0.016, 0.026, and 0.046/h. Oligonucleotide probes to species-specific 16S rRNAs were used to estimate both the cellulose-adherent and nonadherent (planktonic) populations. F. succinogenes S85 represented 52-74% of the adherent population, and 41- 68% of the planktonic population. R. albus 7 accounted for 22-45% of the adherent population and 27-45% of the planktonic population. R. flavefaciens FD-1 was present in both adherent and planktonic populations, but usually at <5% of each population. The data indicate that all three strains can coexist under steady-state conditions. The similar distribution of the three strains in the adherent and planktonic populations suggest that these strains are competing within the same niche rather than interacting as specialist populations preferring cellulolytic or cellodextrin-fermenting (non-cellulolytic) growth modes.