Isolation and characterization of extracellular polysaccharides produced by Pseudomonas fluorescens Biovar II

Extracellular polysaccharides (EPS) were isolated from Pseudomonas fluorescens Biovar II through repeated ethanol precipitations. The neutral monosaccharides in the EPS that were determined by GC–MS consisted of rhamnose, fucose, ribose, arabinose, xylose, mannose, galactose and glucose. The acidic groups in the EPS were mainly composed of carboxylic acid and other minor polyanionic groups, e.g. sulphate and phosphate. Up to 70% of total carbohydrates were uronic acids, and total carbohydrates made up 26–31% of organic carbon. Besides the neutral and acidic sugars in the EPS, EPS also contained 2% of proteins in terms of carbon. The characterization of the main components of the EPS should increase our understanding of the potential binding sites for trace metals and radionuclides to these exopolymeric biosorbents.