The Cellulolytic Activity of Pure Strains of Bacteria from the Rumen of Cattle.

The in vitro breakdown of degraded and undegraded varieties of cellulose was examined by using pure strains of bacteria isolated from the rumen of cattle. One strain of Bacteroides succinogenes, two strains of Ruminococcus albus and two strains of Ruminococcus jlavefaciens were allowed to ferment ground cellulose powder (prepared from filter paper), cellulose powder (Whatman) and undegraded cotton fibres, the extent of breakdown being followed by loss of weight of the insoluble substrate. All five organisms were highly active on degraded ground cellulose powder and dissolved 72-90 yo, but only one organism, B. succinogenes strain s-85, was equally effective on cellulose powder (Whatman) or on undegraded cotton fibres. R. jlavefaciens strain FD-1 was somewhat less potent on the latter substrates, achieving 40 and 60 yo dissolution, respectively, of cellulose powder (Whatman) and cotton fibres. R. albus strain 7 and R. Jlavefaciens strain c-94 had negligible effects on cotton fibres (10 and 0 Yo solubilization, respectively). R. albus strain D-89, producing 40 yo solubilization of cotton fibres, was intermediate in activity between R. albus strain 7 and R. Jlavefaciens strain FD-'I. Cell-free preparations from culture filtrates of B. succinogenes strain s-85 gave only 4 yo breakdown of ground cellulose powder and up to 9 yo breakdown of cellulose powder (Whatman) in 17 days. Cell-free filtrates from the metabolism fluid of R.flavefaciens strain FD-1 or from the disintegrated organisms brought about 46 and 36 yo solubilization, respectively, of ground cellulose powder, but failed to attack cotton fibres. The results support the view that the capacity of an organism or cell-free enzyme to attack any one particular form of cellulose is no criterion of its ability to attack less degraded or undegraded types of cellulose.