Preparation and partial structural characterization of the exopolysaccharide from Bacillus mucilaginosus SM-01

•An acidic hetero-exopolysaccharide (BMPS) was produced and purified from Bacillus mucilaginosus SM-01.•BMPS was mainly compromised of Glc, Man, GlcA with Mw of 2.67 × 106 Da.•A neutral fragment (BMPS-H) was obtained by mild acid hydrolysis of BMPS.•The chemical structure of BMPS-H was characterized to be•Figure optionsDownload full-size imageDownload as PowerPoint slide

In this study, an acidic hetero-exopolysaccharide, designated as BMPS, was isolated from the culture supernatant of bacteria Bacillus mucilaginosus SM-01 by ion-exchange and size-exclusion chromatography. The molecular weight of BMPS was measured to be 2.67 × 106 Da. To analyze the structure of the polysaccharide, the low-molecular weight fragment (BMPS-H) of BMPS was obtained under mild hydrolysis. BMPS-H was determined to be a liner neutral fraction with an average molecular weight of 1621 Da. Monosaccharide analysis indicated that BMPS-H contained glucose and mannose in a molar ratio of 1.5:1. Based on methylation analysis and NMR spectroscopy data, the following structure of BMPS-H was established:Figure optionsDownload full-size imageDownload as PowerPoint slideIn addition, MALDI-TOF-MS analysis showed the hydroxyl group on C-2 of 1,4-linked-glucosyl residues was partially acetylated.