Molecular Identification of Indigenous Lactic Acid Bacteria, Partial Purification and Characterization of β-Galactosidase Produced

Abstract

<p>β-Galactosidase is enzyme which hydrolyze lactose to glucose and galactose, as lactose hydrolyzer. To know indigenous lactic acid bacteria (LAB) characteristics, indigenous LAB identification, partial purification and characterization of β-galactosidase produced was researched. LAB was molecularly identified, β-galactosidase partial purification was conducted by precipitation followed dialysis. β-Galactosidase characterization was based on optimum activities of pH and temperature. The results show that LAB was identified as <em>Lactobacillus plantarum</em> B123. Optimum activity of precipited β-galactosidase was reached at 50 % ammonium sulphate. Activity and specific activity of 50 % precipited β-galactosidase were 95.675 U · mg<sup>–1</sup> and 32.268 U · mg<sup>–1</sup>, respectively. Precipited β-galactosidase resulted a purification level of 3.99 fold, a yield of 38.73 %, and a specific activity of 32.27 U · mg<sup>–1</sup> protein, while dialyzed β-galactosidase resulted 7.61 fold, 10.67 %, and 61.53 U· mg<sup>–1</sup> protein. Optimum temperature and pH for crude β-galactosidase were found at 55 °C and 7.0, respectively, while that dialyzed β-galactosidase were optimized at 50 °C and 7.0. Based on partial purification and characterization, <em>Lactobacillus plantarum</em> B123 is indigenous LAB which good for production of β-galactosidase.</p><div><p class="Els-keywords"><em> </em></p><p class="Els-keywords"><strong>Keywords:</strong> characterization; dialysis; lactic acid bacteria; <em>Lactobacillus plantarum</em> B 123; β-galactosidase.</p></div>