Synthesis of oligosaccharides by growing cultures of Betacoccus arabi nosaceous.

Abstract

KOEPSELL et al. 1 have shown recently that oligosaccharides are formed when the dextransucrase of Leuconostoc mesenteroides (NRRL B-512) acts on sucrose in the presence of certain simple sugars, which serve as chain-initiators. We have observed a similar phenomenon with the dextransucrase and with growing cultures of Betacoccus arabinosaceous (Birmingham strain). When grown on a medium containing sucrose (10 per cent), yeast extract and inorganic salts, this organism produces a dextran in which the principal glucosidic linkages are α-1:6 and the branch points involve positions 1 and 32. Fructose, traces of glucose and a ketose-containing disaccharide can be detected in the medium. The degree of branching in the polysaccharide is dependent, inter alia, on the magnesium content of the medium; dextran samples produced from magnesium-rich and magnesium-deficient media have been proved to have average chain-lengths of 6–7 and 40–50 anhydroglucose units, respectively3.