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1678916 
Journal Article 
Purification and characterization of a novel beta-galactosidase from Bacillus sp MTCC 3088 
Chakraborti, S; Sani, RK; Banerjee, UC; Sobti, RC 
2000 
Yes 
Journal of Industrial Microbiology and Biotechnology
ISSN: 1367-5435
EISSN: 1476-5535 
24 
1 
58-63 
WOS:000086864300011 
An extracellular beta-galactosidase which catalyzed the production of galacto-oligosaccharide from lactose was harvested from the late stationary-phase of Bacillus sp MTCC 3088. The enzyme was purified 36.2-fold by ZnCl2 precipitation, ion exchange, hydrophobic interaction and gel filtration chromatography with an overall recovery of 12.7%, The molecular mass of the purified enzyme was estimated to be about 484 kDa by gel filtration on a Sephadex G200 packed column and the molecular masses of the subunits were estimated to be 115, 86.5, 72.5, 45.7 and 41.2 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isoelectric point of the native enzyme, determined by polyacrylamide gel electrofocusing, was 6.2, The optimum pH and temperature were 8 and 60 degrees C, respectively. The Michaelis-Menten constants determined with respect to o-NO2-phenyl-beta-D-galactopyranoside and lactose were 6.34 and 6.18 mM, respectively, The enzyme activity was strongly inhibited (68%) by galactose, the end product of lactose hydrolysis reaction. The beta-galactosidase was specific for beta-D anomeric linkages, Enzyme activity was significantly inhibited by metal ions (Hg2+, Cu2+ and Ag+) in the 1-2.5 mM range. Mg2+ was a good activator. Catalytic activity was not affected by the chelating agent EDTA. 
purification; extracellular beta-galactosidase; o-NO2-phenyl-beta-D-galactopyranoside; lactose; Bacillus sp