Diversity of extracellular proteolytic activities among Prevotella speciesfrom the rumen

The current research was aimed at comparing proteolytic activities among ru minal Prevotella spp. Growth rates of Prevotella sp. 2202, Prevotella rumin icola D31d, P. brevis GA33, P. albensis M384, and P. bryantii B(1)4 varied with N source, and no one N source produced the fastest growth in all speci es. Proteolytic activity was greatest with casein compared with peptides, A A, and NH4Cl in all species. Proteolytic activity of Prevotella sp. 2202, P . brevi GA33, and P. bryantii B(1)4 was modulated by N source. With gelatin co-polymerized SDS-PACE, the extracellular activities of the Prevotella sp p. showed wide variation in number, size, and type of proteases. Prevotella sp. 2202 and P. albensis M384 produced metalloproteases of low molecular w eight (40 kDa). P. ruminicola D31d produced one cysteine protease (100-200 kDa) and two metalloproteases (90-100 kDa). P. brevis GA33 generated a diff use clearing zone (95-160 kDa) containing serine, cysteine, and metalloprot eases. P. bryantii B(1)4 produced a metalloprotease greater than 200 kDa in size. The molecular sizes provided are estimations and served only to diff erentiate among the bacterial species in this study. Large variations in pr oteolytic activities among species and the known genetic diversity of the P revotella taxon suggested that targeting this bacterial assemblage for gene tic manipulation in order to alter the bacterial impact on ruminal protein degradation would be difficult.