Production and characterization of a thermostable beta-galactosidase from Bacillus coagulans RCS3.
A strain of Bacillus coagulans RCS3 isolated from a hot-water spring produced significant beta-galactosidase activity at 10 days of growth in a flask. While enzyme production was maximum at 50 degrees C, the highest activity was at 65 degrees C, where the half-life was 2 h. A 2 degrees C decrease in temperature increased the half-life to 15 h without significantly changing the activity, suggesting that 63 degrees C is the temperature of preference compared with 65 degrees C for a combination of good activity and stability. The beta-galactosidase was also stable over pH 5-8, with peak activity at pH 6-7. It was strongly and competitively inhibited by the hydrolysis product galactose. Bivalent cations (Cu(2+), Ni(2+) and Hg(2+)) in the concentration range of 0.5-2.0 mM also inhibited enzyme activity. Both lactose solution and whey could be hydrolysed substantially within 36 h at 50 degrees C. The thermostability and pH-stability and good hydrolytic capability make this enzyme potentially useful in the dairy industry.
Batra
Navneet
N
Department of Biotechnology, Panjab University, Chandigarh, India.
Singh
Jagtar
J
Banerjee
Uttam C
UC
Patnaik
Pratap R
PR
Sobti
Ranbir C
RC
D000818:Animals; D001407:Bacillus / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D050260:Carbohydrate Metabolism; D004795:Enzyme Stability; D005690:Galactose / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008670:Metals / Q000494:pharmacology; D008892:Milk / Q000378:metabolism; D011786:Quality Control; D012680:Sensitivity and Specificity; D013696:Temperature; D001616:beta-Galactosidase / Q000037:antagonists & inhibitors / Q000302:isolation & purification* / Q000378:metabolism*
D008670:Metals; D001616:beta-Galactosidase; D005690:Galactose