Abstract



Dextran a bacterial exopolysaccharide and a polymer of glucose is produced by different microorganisms like Leuconostoc mesentiroides, Lactobacillus spp, Weissella spp etc. It has a wide range of applications in the food, pharmaceutical and other industries. Dextran and its derivatives like iron dextran, clinical dextran, food grade dextran are rapidly emerging as new and industrially significant products. In the present study different carbon sources like sucrose, glucose, maltose and lactose were studied for their effect on dextran production and dextransucrase activity. Results indicated that 4% sucrose concentration had an inducing effect on both dextran production and dextransucrase activity. Further study was done to screen for cheap sucrose source using statistical design like Plackett-Burman. A twelve experimental design of Plackett-Burman was used and eleven sources like guava, pineapple, sugarcane, apple, orange, sapota, white grapes, banana, black grapes, sweet lime and pomegranate were screened. Broth analysis indicated presence of more fructose and less glucose as glucose was used for dextran production. Dextran was recovered from broth by alcohol precipitation. The results indicated that there was higher dextran production in sugarcane and sapota. These studies indicate that such sucrose rich cheaper sources can be used for commercial production of dextran.