The authors previously, achieved a high yield of exopolysaccharide production from a marine Klebsiella sp. The aim of the present study is determination of this exopolysaccharide composition and evaluation of its biological activities. The monosaccharide moieties of this exopolysaccharide were determined by complete hydrolysis, qualitative and quantitative paper chromatography of the hydrolysis product. The monosaccharide composition of this exopolysaccharide was galactose 16%, fructose 20%, glucose 32%, fucose 22%, and uronic acid 10%. The biological activities of the native and modified sulfated bacterial exopolysaccharide were investigated. No anticoagulation or fibrinolytic activities were recorded for the sulfated exopolysaccharide, but the native form of exopolysaccharide showed both activities. The native exopolysaccharide also showed higher antibacterial activity against S. aureus and E. coli but both the native and sulfated form had no antifungal activity against Candida albicans. MIC of the native and sulfated exopolysaccharide that sustain the highest bacterial inhibition zone was 15 mg/dl. No prebiotic activities were recorded for both. In conclusion, this biopolymer has significant biological activities and it has two rare monosaccharide moieties with very significant value namely fucose and uronic acid that require further adaptation for practical and industrial application.
Key words: Antimicrobial, Biological activities, Exopolysaccharide, Klebsiella sp, Marine.
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