The influence of carbon source and of the conditions for fermentation on the production of exopolysaccharides.

Abstract

The synthesis of exopolysaccharides was determined for the strains Lactobacillus sp. IL1, Lactobacillus sp. IL4 in MRS medium having glucose, lactose and sucrose as carbon sources. From the results obtained it was highlighted the fact that, by using sucrose as carbon source, the biggest quantity of exopolysaccharides is obtained, namely 41 mg/L and, respectively, 74 mg/L. The influence of different concentrations of sucrose (5, 10, 15, 20%) on the production of exopolysaccharides was tested. It resulted that for a concentration of 15% sucrose, a maximum of the quantity of synthesized exopolysaccharides is obtained. Also, the influence of temperature and pH on the capacity to synthesized exopolysaccharides for the used strains was tested. From the determinations made it resulted that a temperature of 370C and a pH of 7 represent the ideal parameters so as to obtain a maximum quantity of exopolysaccharides, in the case of using MRS with 15% sucrose. 55 mg/L are obtained, for the strain Lactobacillus sp. IL1 and 145 mg/L, for the strain Lactobacillus sp. IL4.