Dextranase: Hyper production of dextran degrading enzyme from newly isolated strain of Bacillus licheniformis

Dextranase, 6-alpha-D-glucan 6-glucanohydrolase catalyzes the degradation of dextran (polymer of D-glucose) in to low molecular weight fractions. Dextranolytic bacterial strains were isolated from various natural sources and plate assay methods were developed for screening of highest extracellular dextranase producing isolate. Bacillus licheniformis, identified on the basis of taxonomic characterization was subjected to UV radiation and highest enzyme producing mutant obtained led to 7 times more dextranase production than wild. Optimization of major physico-chemical parameters affecting enzyme production; including medium composition, pH, cultivation time and temperature revealed that maximum enzyme production was obtained in a self designed medium (pH 6.0) containing 1% Dextran 5000 Da, after 24 h culture incubation at 37 degrees C. Dextranase reported in this study is of great commercial importance as it is strictly inducible in nature and B. licheniformis being non-pathogenic removes the safety concerns associated with production of dextran fractions for clinical and pharmaceutical usage. (C) 2012 Elsevier Ltd. All rights reserved.