OPTIMIZATION OF CONDITIONS OFLEUCONOSTOC MESENTEROIDESNRRL B-640 FOR PRODUCTION OF A DEXTRANSUCRASE AND ITS ASSAY

Abstract

ABSTRACT The optimum culture conditions for dextransucrase production from Leuconostoc mesenteroides NRRL B-640 were investigated. The dextransucrase production was studied in the temperature range, 22 to 30C under shaking and static flask conditions. The optimum temperature for dextransucrase production was 25C. The shaking flask culture gave higher enzyme activity by 20% than the static flask culture. The dextransucrase activity of L. mesenteroides NRRL B-640 was compared with L. mesenteroides NRRL B-512F. The results showed that the maximum dextransucrase activity achieved by L. mesenteroides NRRL B-640 at 25C under shaking flask culture, was 15% higher than that the enzyme activity given by L. mesenteroides NRRL B-512F grown at 23C under the static flask culture. The dextransucrase elaborated by L. mesenteroides NRRL B-640 displayed a maximum enzyme activity when assayed in the temperature range of 30 to 35C and at pH of 5.4. The enzyme was stable with in the 10–500 mM concentrations of sodium acetate buffer. PRACTICAL APPLICATIONS Dextransucrase synthesizes dextran that has several commercial applications in both its native and modified forms. Flocculation agent in waste-water treatment, blood volume expander, stabilizer in ice cream and a cryo-protective agent for cells are a few of dextran applications in its native form. It can serve as stabilizer in photographic, cosmetics and agriculture-based industries with generation of charged derivatives of dextran. Dextransucrases are reported to generate varieties of gluco-oligosaccharides that serve as prebiotics. Dextransucrases are reported in the glycoconjugation of several peptides for the development of vaccines, contraceptives and antibiotics. Dextran conjugates with iron and fluorophores are used in the clinical applications. Dextran hydrogels are used in pharmaceutical and biomedical applications such as contact lenses and in drug delivery. Looking at the wide applications of dextransucrase and growing demand there is a need for exploration of new strains for production of efficient and pure dextransucrase, producing better quality and yield of oligosaccharides and polysaccharides. The results of optimized conditions attain importance for large-scale production of dextransucrase.