<img src='/image/spc_char/beta.gif'>-Galactosidase from <i style="">Lactobacillus acidophilus </i>isolated from fermented ragi (<i style="">Eleusine coracana</i>)

Abstract

<i style="">Lactobacillus acidophilus</i> was isolated from fermented millet, <i style="">Eleusine coracana</i>. It was characterized using several biochemical tests. This strain was found to be homofermentative, slime forming and <img src='/image/spc_char/beta.gif'>-galactosidase producer. Recovery and characterization of <img src='/image/spc_char/beta.gif'>-galactosidase were studied at laboratory scale. Since the enzyme was intracellular various cell lysis methods were studied to achieve maximum enzyme release from cell fragments. Homogenization at a pressure of 2000 psig two passes showed an enzyme release of 2050 U/mL and was found the best method for cell lysis. The cell extract was purified using ultrafiltration and gel permeation chromatography. Specific activity and fold purification of <img src='/image/spc_char/beta.gif'>-galactosidase was found to be 568.61 and 21.2, respectively. Kinetic parameters were determined using ONPG (o-nitrophenyl galactopyranoside) as a substrate. Michaeli’s Menten equation was found to fit the reaction of ONPG using <img src='/image/spc_char/beta.gif'>-galactosidase from <i style="">L. acidophilus. </i>Vmax and Km were calculated from the Lineweaver Burk plot. Vmax was found to be 4.94 min^-1 and Km to be 0.11 m<i style="">M</i>. Using gel permeation chromatography, the molecular weight was found to be in the range of 450-500 kDa.