Fibrobacter is genus of gram-negative, anaerobic bacteria in the family Fibrobacteraceae, commonly isolated from the human gastrointestinal tract. The Fibrobacteres phylum contains two species F. succinogenes and F. intestinales which are cellulose degraders found in the rumen and termite gut. Both species are rather difficult to isolate into pure culture due to the specifics of agar and apparent symbiosis with other rumen bacteria. Attempts have been made to isolate Fibrobacter species from environments other than the herbivore gut. 1

In the rumen, Fibrobacter can use a variety of complex substrates and fixes CO2 during succinate production. In general, Fibrobacter strains produce more succinate at a higher rate than Ruminococcus. Fibrobacter succinogenes, a Gram-negative, anaerobic ruminal bacterium is a major fibre digesting species in the rumen. It intensively degrades plant cell walls by an erosion type of mechanism, burrowing its way through the complex matrix of cellulose and hemicellulose with the release of digestible and undigested cell wall fragments. The enzymes involved in this process include a combination of glucanases, xylanases, arabinofuranosidase(s) and esterases.

Source: CDC

Members of the bacterial genus Fibrobacter have also been detected in other environments such as landfill sites, demonstrating the fact that Fibrobacter species can be a significant component of the microbial community in landfill ecosystems. Their diversity and abundance points to a possible role in cellulose hydrolysis in landfill, and perhaps other anaerobic environments also.


  1. Methods in Enzymology: Cellulases. v.510. H. J. Gilbert
  2. Fibrobacter succinogenes, a Dominant Fibrolytic Ruminal Bacterium: Transition to the Post Genomic Era. H. S. Jun et al.
  3. Detection of novel Fibrobacter populations in landfill sites and determination of their relative abundance via quantitative PCR. James E. McDonald et al.



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