Cell-wall polysaccharides purified from four species of the genus
Microbacterium were characterized in relation to their taxonomy, based on
1H-NMR and
13C-NMR spectrometry, methylation analysis and Smith degradation.
The polysaccharide isolated from
M. imperiale IFO 12610 contained a backbone consisting of heptasaccharide repeating-units, to which side chains of L-rhamnopyranosyl-(1→2)-D-mannopyranosyl-(1→2)-D-mannopyranoses as branches were attached to position 6 of the 3-linked D-galactopyranose residues. The polysaccharide of
M. lacticum IFO 14135 contained hexasaccharide repeating-units, to which disaccharide groups of L-rhamnopyranosyl-(1→2)-L-rhamnopyranoses were attached to position 6 of the 3-linked D-galactopyranose residues to form branches. The polysaccharide of
M. arborescens IFO 3750 consists of pentasaccharide repeating-units, and single D-mannopyranosyl groups were attached as branches to position 6 of the 3-linked D-galactofuranose residues. The polysaccharide of
M. laevaniformans IFO 14471 had a more complicated structure consisting of decasaccharide repeating-units, and branches occur at three different positions.
Thus, the cell-wall polysaccharides of the former three species were similar in their basic structures, but that of
M. laevaniformans has a significantly different structure. These results indicated that the structures of cell-wall polysaccharides are heterogeneous in the genus
Microbacterium and may characterize the species in the genus.
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