Emulsifying and Cell Proliferative Abilities of the Exopolysaccharide Produced by Leguminous Plant Nodule Associated Bacterium Cronobacter sp.

Exopolysaccharides (EPS) produced by bacteria are high molecular weight secondary metabolites having wide applications in food and pharmaceutical industry. In the present study, an exopolysaccharide producing bacterium was isolated from the root nodules of a leguminous plant and was studied for emulsification activity and biocompatibility using human dermal fibroblasts. Under optimum culture conditions, the purified EPS yield in modified YEM media was 2.8 g L and was identified as β-glucan with the molecular weight 15.57 × 10 Da. The EPS showed high emulsifying activity against hydrocarbons such as petrol, kerosene, xylene, palm oil, coconut oil, and olive oil with emulsification index > 60% at 0.25 and 0.5% concentrations at 25 °C. The EPS was sensitive to high temperature, but the emulsions were stable at pH range 2–9 and in the salinity range of 1–20%. In vitro cell viability studies indicated that EPS was not cytotoxic at tested concentrations on human dermal fibroblasts moreover, it had proliferative activities. Hence, the EPS from Cronobacter sp. can be a good candidate for biotechnological application as a source of β-glucan with emulsifying and tissue regenerative properties.