Emulsifying behavior of an exopolysaccharide produced by Enterobacter cloacae

A major concern for industrial production of microbial emulsifiers is expensive substrates. The aim of this work was to produce a microbial exopolysaccharide (EPS) using sea broth. Seawater, seawater + distilled water and nutrient broth were inoculated with Enterobacter cloacea and incubated in a rotary shaker at 37°C for 80 h. The microorganism produced different amount of exopolysaccharide in different ratios of distilled water and seawater but there was no any production in the nutrient broth. The best result was obtained in the sea water broth without addition of distilled water. Stability of emulsions formed with corn oil and toluene was studied at different concentration of EPS (15 - 75) and in the presence of sodium chloride (5 – 40 mg ml-1). The exopolysaccharide efficiently emulsified corn oil and toluene with water and salty solutions. There was a linear correlation between the concentration of EPS 71a and emulsification indices. The presents of salt up to 40 mg/ml did not show remarkable decrease in emulsion indices. This result suggests that the produced exopolysaccharide has a good potential to be used in the food industry.