The Karachi Institute of Biotechnology and Genetic Engineering (KIBGE), University of Karachi, Karachi 75270, Pakistan.
Carbohydr Polym. 2013 Feb 15;92(2):2149-53. doi: 10.1016/j.carbpol.2012.11.044. Epub 2012 Nov 23.
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 °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.
葡聚糖酶,6-α-D-葡聚糖 6-葡聚糖水解酶,可催化葡聚糖(D-葡萄糖聚合物)降解为低分子量片段。从各种天然来源中分离出葡聚糖酶产生菌,并开发了平板检测方法,用于筛选产胞外葡聚糖酶活力最高的菌株。根据分类特征鉴定的地衣芽孢杆菌经紫外线照射后,获得的产酶活力最高的突变株比野生型酶活力提高了 7 倍。优化影响酶生产的主要理化参数;包括培养基组成、pH 值、培养时间和温度,结果表明,在 pH 值为 6.0 的自行设计的培养基(含 1%的 5000Da 葡聚糖)中,37°C 培养 24 小时后,可获得最大酶活。本研究中报道的葡聚糖酶具有重要的商业价值,因为它在性质上是严格诱导的,而且地衣芽孢杆菌是非致病性的,消除了与临床和制药用途的葡聚糖片段生产相关的安全问题。