Application of response surface methodology for maximizing dextransucrase production from Leuconostoc mesenteroides NRRL B-640 in a bioreactor.

The production of dextransucrase from Leuconostoc mesenteroides NRRL B-640 was investigated using statistical approaches. Plackett-Burman design with six variables, viz. sucrose, yeast extract, K(2)HPO(4), peptone, beef extract, and Tween 80, was used to screen the nutrients that significantly affected the dextransucrase production. 2(4)-Central composite design with four selected variables (sucrose, K(2)HPO(4), yeast extract, and beef extract) was used for response surface methodology (RSM) for optimizing the enzyme production. The culture was grown under flask culture with 100 ml optimized medium containing 30 g/l sucrose, 18.5 g/l yeast extract, 15.3 g/l K(2)HPO(4), and 5 g/l beef extract at 25 degrees C and shaking at 200 rpm gave dextransucrase with specific activity of 0.68 U/mg. Whereas the same optimized medium in a 3.0-l bioreactor (1.4 l working volume) gave an experimentally determined value of specific activity of 0.70 U/mg, which was in perfect agreement with the predicted value of 0.65 U/mg by the statistical model.