Optimization and Statistical Evaluation of Medium Components Affecting Dextran and Dextransucrase Production by Lactobacillus acidophilus ST76480.01
Rania M.A. Abedin1, Aliaa M. El-Borai2, Mona Abo Shall3, Samy A. El-Assar4
1,2,3,4 Botany and Microbiology Department, Faculty of Science, Alexandria University, Egypt.
Abstract: On the basis of high enzyme activity a newly isolated strain was selected for dextran and dextransucrase production. Morphological, biochemical, and 16S rRNA sequencing analysis identified the strain as Lactobacillus acidophilus ST76480.01. It produced maximum dextran after 48 hours of incubation in the presence of sucrose as a carbon source, yeast extract and peptone as a nitrogen source at 30°C and pH 8.3. Present study reported statistical medium optimization for dextran and dextransucrase production for the strain comprising of Plackett-Burman. The increasing in sucrose concentration was significant for maximum dextran yield (4.24 mg/mL) and the highest dextransucrase activity (4.64 DSU/mL/hr) were obtained when 15% sucrose concentration was used while, the decreasing of K2HPO4 was significant for the highest dextransucrase activity (4.45 DSU/mL/hr) and (4.34 mg/mL) of dextran yield was obtained at (10 g/L) of K2HPO4.The structure of the polysaccharide dextran polymer was analyzed by 13C nuclear magnetic resonance (NMR) spectroscopic techniques. It was confirmed that the insoluble dextran produced by Lactobacillus acidophilus ST76480.01showed six major resonance peaks at 500 MHz: 104.245, 80.437, 76.192, 75.353, 63.258 and 59.739 ppm for linear linkages and the spectra of insoluble dextran was also found to contain minor peaks indicative of branching.
[Rania MA Abedin, Aliaa.MA El-Borai, Mona Abo Shall, Samy El-Assar. Optimization and Statistical Evaluation of Medium Components Affecting Dextran and Dextransucrase Production by Lactobacillus acidophilus ST76480.01. Life Sci J 2013; 10(1):1746-1753] (ISSN: 1097-8135). http://www.lifesciencesite.com
Key words: Dextran; dextransucrase; Lactobacillus acidophilus ST76480.01; Plackett-Burman