Purification and characterization of maltooligosaccharide-forming amylase from Bacillus circulans GRS 313 |
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Authors: | G Dey S Palit R Banerjee BR Maiti |
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Institution: | (1) Microbial Biotechnology and Downstream Processing Laboratory, Agricultural and Food Engineering Department, IIT-Kharagpur 721302, India, IN;(2) Chemical Engineering Department, IIT-Kharagpur 721302, India, IN |
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Abstract: | A maltooligosaccharide-forming amylase that hydrolyzes starch into maltotriose and maltopentaose was found in the culture
filtrate of a strain of Bacillus circulans GRS 313 isolated from local soil. The enzyme was purified by organic solvent fractionation, Sephadex G-100 gel filtration
and CM-Sephadex column chromatography. Optimum pH and temperature of amylase were evaluated using response surface methodology
(RSM) and were found to be 48°C and 4.9, respectively. The enzyme was stable up to 60°C and its pH stability was in the range
of 5.0–8.0. The K
m and V
max of the amylase with starch were 11.66 mg/ml and 68.97 U, respectively, and the energy of activation, E
a, was 7.52 kcal/mol. Dextrin inhibited the enzyme competitively, with a K
i of 6.1 mg/ml, and glucose caused noncompetitive inhibition with a K
i of 9.5 mg/ml. The enzyme was inhibited by Hg2+, Mn2+, Fe3+ and Cu2+ and enhanced by Co2+ and Mg2+. EDTA reversed the inhibitory effect of the metals. Paper chromatographic and high-performance liquid chromatography analysis
of the products of the amylolytic reaction showed the presence of maltotriose, maltotetraose, maltopentaose, maltose and glucose
in the starch hydrolysate. Journal of Industrial Microbiology & Biotechnology (2002) 28, 193–200 DOI: 10.1038/sj/jim/7000220
Received 11 December 2000/ Accepted in revised form 22 October 2001 |
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Keywords: | : maltooligosaccharide-forming amylase B circulans GRS 313 |
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