The characteristics of lactate-fermenting sporeforming anaerobes from silage.

In studies on the sporeforming anaerobic bacteria in orchard grass silages, two groups were found to predominate on the basis of spore counts (Bryant et at., 1952). Several proteolytic strains isolated were similar to Clo8tri4ium sporogenes, but the majority of isolates were lactatefermenting anaerobes which were similar to Clostridium tyrobutyricum (van Beynum and Pette, 1935). Since the work of van Beynum and Pette (1935, 1936), lactate-fermenting, sporeforming anaerobes have been isolated from silage by Martos (1941) and Rosenberger (1951), but descriptions of additional characteristics of these organisms were not given. The current edition of Bergey's Manual (Breed et al., 1948) does not recognize C. tyrobutyricum as a separate species but places it in the appendix to the species C. butyricum, even though it ferments lactate and ferments few carbohydrates, while C. butyricum ferments many carbohydrates and supposedly not lactate. Bhat and Barker (1947) showed that the fermentation of lactate by a sporeforming anaerobe from soil, Clostridium lacto-acetophilum, was dependent on the presence of acetate in the medium. These organisms were identical with C. butyricum (Breed et at., 1948) except for the fermentation of lactate. They did not test known strains of C. butyricum for fermentation of lactate under their conditions. The purpose of the present work is to determine the characteristics of the lactate-fermenting clostridia in grass silage to obtain a better understanding of the species involved.