Structural studies of the exocellular polysaccharide from Sphingomonas paucimobilis strain I-886

The exocellular polysaccharide from Sphingomonas paucimobilis strain I-886 has been studied using methylation analysis, Smith degradation, partial acid hydrolysis, NMR spectroscopy, and mass spectrometry as the principal methods. It is concluded that the repeating unit has the following structure: [formula: see text] The absolute configuration of the uronic acid was deduced from 1H NMR chemical shifts and is most likely D. Some preparations of the polysaccharide also contain phosphate and O-acyl groups which have not been identified or localised.