Open AccessISOLATION AND PURIFICATION OF LACTASE FROM LACTOBACILLUS ACIDOPHILUS
Author(s) -
Linh Thi Nguyen,
Dung Nguyen,
Lam Bich Tran
Publication year - 2012
Publication title -
khoa học công nghệ
Language(s) - English
Resource type - Journals
ISSN - 1859-0128
DOI - 10.32508/stdj.v15i3.1818
Subject(s) - chemistry , chromatography , lactobacillus acidophilus , lactase , enzyme , enzyme assay , gel permeation chromatography , lactobacillaceae , extraction (chemistry) , food science , biochemistry , lactobacillus , bacteria , fermentation , biology , organic chemistry , probiotic , genetics , polymer
The enzyme β-galactosidase (β-D-galactoside galactohydrolase, EC 3.2.1.23) commonly known as lactase, has important applications in the dairy industry. From culture of strain Lactobacillus acidophilus having high and stable β-galactosidase activity, the study of crude enzyme isolation were carried out by ultrasonical extraction and precipitation by neutral salts and organic solvents. Best precipitant was isopropanol with enzyme recovery 89,93%, and enzyme purity increased 4,5 folds. Further β-galactosidase purification was carried out using gel permeation chromatography on Ultrahydrogel 250 to increase purity in 14,3 folds. The molecular weight of β-galactosidase was 40 kDa. The purified enzyme had optimum activity at 40oC, pH 7 – 7,5 and kinetic parameters of Vmax and Km were 2,3 μmol/min and 0,73 mM.