Structural Analysis of the Water-soluble Carbohydrate from Asaia bogorensis by NMR Spectroscopy

Abstract

The water-soluble extracellular polysaccharide produced by Asaia bogorensis, an acetic acid bacterium, was investigated. It was suggested that the water-soluble polysaccharide seemed to be a fructan as only fructose was detected as a constituent sugar when it was hydrolyzed by trifluoroacetic acid. To confirm the glycosidic linkage of the fructan, ¹H NMR spectroscopy and ¹³C NMR spectroscopy were carried out. From these results, Asaia fructan was identified as levan, which is a β-2,6 linked fructan, similar to the polysaccharide produced by Gluconacetobacter xylinus. This β-2,6-linked levan-type fructan was produced only when sucrose was used as a carbon source.