DISTRIBUTION OF CELLULOSE-BINDING PROTEINS AMONG THE REPRESENTATIVE STRAINS OF RUMEN BACTERIA

The presence or absence of cellulose-binding proteins (CBPs) in the cell lysate of 31 strains representing 17 species of rumen bacteria was examined. Both carboxymethylcellulose (CMC) and sodium dodecyl sulfate (SDS) were used to elute CBPs of these bacteria from cellulose. For 16 strains classified into 4 species of Fibrobacter succinogenes, Fibrobacter intestinalis, Ruminococcus flavefaciens and Eubacterium cellulosolvens, the SDS-polyacrylamide gel electrophoresis (SDS-PAGE) patterns of the CMC-eluted CBPs were identical with those of the SDS-eluted CBPs. For 4 strains representing 4 species of VEillonella parvula, Megasphaera elsdenii, Prevotella ruminicola subsp. ruminicola and Eubacterium ruminantium, the SDS-PAGE patterns of both the CMC-eluted CBPs and the SDS-eluted CBPs were different. In the case of 3 strains representing Ruminococcus bromii, Butyrivibrio fibrisolvens and Ruminobacter amylophilus, CBPs were eluted only with SDS from cellulose, but not with CMC. On the other hand, none of the other strains tested contained a detectable amount of CBPs. Western immunoblot analysis indicated that CBP (120 kDa) of both the 10 strains of F. succinogenes and 1 strain of F. intestinalis was antigenically identical with CBP1 of F. succinogenes S85, and CBPs of other bacteria did not cross-react with rabbit antiserum to CBP1.