Polysaccharides synthesized by aerobic mesophilic spore-forming bacteria.

In the classification proposed by Smith, Gordon & Clark (1946) the genus Bacillus has been divided into three groups depending principally on morphological differences in the size and shape of the spores and the shape of the sporangia. Their classification and nomenclature has been used throughout this paper. The bacilli of group I are known to synthesize fructosans from sucrose; those obtained from B. 8ubtili8, B. megatherium and B. pumilus (mesentericus) have been intensively studied (Harrison, Tarr & Hibbert, 1930; Challinor, Haworth & Hirst, 1934; Lyne, Peat & Stacey, 1940; Evans & Hibbert, 1946) and all have been shown to be levans of the same general structure containing D-fructose as the sole constituent sugar. The same attention has not been paid to the polysaccharides produced by the bacilli of group II. B. polymyxa has been shown to produce a levan from sucrose, and an unidentified polysaccharide which is not a levan from other sugars (Hestrin, AvineriShapiro & Aschner, 1943). Kleczkowska, Norman & Snieszko (1940) isolated a new capsulated bacillus from cultivated soil which they named B. krzemieniewski. In some strains well-defined capsules were present, while in others the mucilage was dispersed throughout the medium. Kleczkowski & Wierzchowski (1940) reported the separation of the capsular polysaccharide, and solely on the optical rotation of the total hydrolysate and the isolation of mannose phenylhydrazone, deduced that the polysaccharide was a mannan composed of L-mannose units. The sugar L-mannose has not been known to occur previously, and it has been commented (Evans & Hibbert, 1946) that such a result requires confirmation. B. krzemieniewski isnow consideredby Smith et al. (1946), pending the study and isolation of more strains, as a mucoid stage of growth of B. circulans. It is classified as B. circulan8 760 in their collection. Group III bacilli do not appear to produce exocellular polysaccharides. It was not our intention to make an intensive structural analysis of any of the polysaccharides produced by the bacilli, but rather, by studying the nature of the constituent sugars, to discover if any correlationexists betweenthegroups ofthe aboveand the type ofpolysaccharide synthesized in presence of various sugars. EXPERIMENTAL