Optimization of EPS production conditions by Leuconostoc dextranicum isolated from traditional Syrian cheese

Increasing demand for industrial applications of various natural polymers has led to increased attention to the use of exopolysaccharides made by microorganisms. Since most lactic acid bacteria (LAB) are food-grade microorganisms with GRAS status (Generally Recognized As Safe), the use of the secreted EPS as natural alternatives to produce all-natural food products without additives from LAB has received increased attention. In this research, carbon and nitrogen sources suitable for the production of exopolysaccharides (EPSs) by Leuconostoc dextranicum, as GRAS bacterium, were investigated. The results showed that glucose (Glu) produced more EPSs in the medium compared to other sugars and peptone compared to other nitrogen sources. Therefore, only glucose and peptone were used to optimize the production conditions of EPSs. In order to investigate the effect and optimization of EPS production conditions, three parameters of temperature, pH and incubation time, each was selected at five levels and optimized separately. Then, optimization was performed to determine the levels at which independent variables attain the best production. Results showed that the best laboratory condition for EPSs production would be yielded at the incubation temperature of 40 °C, pH of 5.5 and fermentation time of 48 hours. In summary, the results of this study showed the potential of Leu. dextranicum as a native microorganism and the cheap culture medium of skimmed milk for producing such a valuable product.