Optimization of Culture Conditions for Exopolysaccharide Production by a Probiotic Strain of Lactobacillus rhamnosus E/N

The effects of culture conditions on exopolysaccharides (EPS) production by a probiotic Lb. rhamnosus E/N have been studied using the Plackett-Burman design. Process optimization was performed in stationary cultures to maximize the production of EPS. In order to verify the optimal conditions, an analysis was performed of EPS production in fermentation culture. Batch fermentation was carried out at working volume of 2.51. The optimal temperature, pH, carbon source, and nitrogen source conditions were 37 degrees C, pH 5.0, galactose, and yeast extract, respectively. EPS production was improved by 210.28 mg/l in stationary cultures compared to 134.2 mg/l in a control grown on commercial MRS medium. The fermentor experiment showed the possibility of increasing EPS biosynthesis by 175.8%. Our results clearly demonstrate that in the case of Lb. rhamnosus E/N specific culture conditions can enhance EPS production for possible application in the industry.