Fibrobacteres

Fibrobacteres is a small phylum of bacteria best known for its type genus, Fibrobacter, whose members are important cellulose degrading inhabitants of the digestive tracts of ruminant animals such as cattle and sheep. Fibrobacter species attach directly to plant fiber and break down cellulose more efficiently than many other gut microbes, making the phylum a significant contributor to how ruminants digest fibrous plant material, though relatively few species outside this specialized niche have been described.