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Thermodynamic characterization of a highly thermoactive extracellular pectate lyase from a new isolate Bacillus pumilus DKS1.

Basu S, Ghosh A, Bera A, Saha MN, Chattopadhyay D, Chakrabarti K

Department of Biochemistry, University College of Science, Calcutta University, 35 Ballygunge Circular Road, West Bengal, Kolkata 700 019, India.

An extracellular pectate lyase (EC 4.2.2.2) was purified from the culture filtrate of a newly isolated Bacillus pumilus DKS1 grown in pectin containing medium. Using ion-exchange and gel filtration chromatography, this enzyme was purified and found to have a molecular weight of around 35kDa. The purified enzyme exhibited maximal activity at a temperature of 75 degrees C and pH 8.5. The presence of 1mM calcium and manganese enhanced pectate lyase activity and was strongly inhibited by zinc, nickel and EDTA. The thermal inactivation studies revealed an entropy-enthalpy compensation pattern below a critical temperature. The alkaliphilicity and high thermostability of this pectate lyase may have potential implications in fibre degumming.

Published 30 April 2008 in Bioresour Technol.
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