Fermentative production of dextran using Leuconostoc spp. isolated from fermented food products

Leuconostoc spp. (LS1and LI1) isolated from sauerkraut and idli batter was selected for dextran production. To enhance the yield of dextran, effects of various parameters such as sucrose concentration, pH, temperature, incubation and inoculum percentage were analyzed. The optimum sucrose concentration for the Leuconostoc spp. (LS1 and LI1) was found to be 15% and 25% respectively. Isolates produced maximum dextran after 20 h of incubation at 29° C and the optimum pH was found between 8 and 8.5. The inoculum concentration of 7.5% was more favorable for the production of dextran by Leuconostoc spp. (LS1 and LI1). The growth kinetic parameters were studied and compared for the strains LS1 and LI1. Mass production of dextran was carried out using a stirred tank batch reactor. FTIR analysis was done to determine the functional groups of dextran. sephadex is prepared by cross linking dextran using epichlorohydrin and the functional groups are determined by FTIR analysis.