Identification of 6-deoxy-D-talose in an extracellular polysaccharide produced by Butyrivibrio fibrisolvens strain X6C61

Abstract An extracellular polysaccharide made by the obligately anaerobic ruminal bacterium Butyrivibrio fibrisolvens was purified by anion-exchange chromatography and found to contain an unknown carbohydrate component. This unknown component was purified to homogeneity by preparative paper chromatography and column chromatography on Dowex 50W-X4-immobilized calcium ions. Reaction in the cysteine-sulfuric acid test suggested that the unknown component was a 6-deoxyhexose, a supposition that was confirmed by electron impact and chemical ionization mass spectrometric studies of alditol acetate derivatives prepared from the unknown sugar. On the basis of results obtained by analytical paper chromatography with three different solvent systems, the unknown was tentatively identified as 6-deoxytalose. The unknown was confirmed as being 6-deoxy- d -talose by g.l.c. analysis of the acetylated glycosides prepared from it and chiral (−)-2-octanol. These were compared with the corresponding sets of diastereometric glycosides of 6-deoxy- d - and - l -talose.