Lipomyces starkeyi 유래의 Dextranase및 amylase의 특성 및 이용 = Characterization and use of the dextranase and amylase from Lipomyces starkeyi mutant

다국어 초록 (Multilingual Abstract)

Endo-dextranase hydrolyzes the α-1.6-glycosidic linkage of dextran and α-amylase hydrolyzes the α-1,4-glycosidic linkage of starch. We have isolated Lipomyces starkeyi JLC 26, a constitutive and hyper-producing mutant for dextranase and amylase from Lipomyces starkeyi ATCC 74054, after mutation using X-ray and UV irradiation followed by zone clearing selection of starch and blue dextran. After partial purification of dextranase and amylase (DXAMase; both activities were always co-purified) by ammonium sulfate precipitation, hydroxyapatite chromatography and Cm-Sepharose chromatography, the specific activities of dextranase and amylase were 120 add 108 IU/mg, respectively. The pH effects for activity and stability of both enzymes from JLC 26 were similar to each other; Optimum pH and temperature for activity were pH 4.0 and 37℃ and for stability were pH 2.5 - 5.5 and 4 - 55℃ respectively. The reaction end products of dextranase and amylase activities were found to typical for those of endo-dextranase and endo-amylase. From dextran, the dextranase produced glucose, isomaltose and isomaltotriose with the relative value of 50.9, 20.4, and 5.5%, respectively. The amylase produced glucose, maltose, and maltotriose with the relative value of 58.3, 5.6, and 11.5%, respectively. Using mixed enzyme system with dextranase, amylase and dextransucrase activities with starch and sucrose, we produced new structural oligosaccharides as well as malto and isomaltooligosaccharides.