Journal of Environmental Biology

Factors influencing production of lipase under metal supplementation by bacterial strain, Bacillus subtilis BDG-8

B. Dhevahi¹* and R. Gurusamy²

¹Department of Science and Humanities, Kongunadu College of Engineering and Technology, Thottiam-621 215, India

²Department of Science and Humanities, Hindusthan Institute of Technology, Coimbatore-641 032, India

*Corresponding Authors Email : dhevahi@gmail.com

  Publication Data

Paper received:

05 March 2013

Revised received:

10 August 2013

Re-revised received:

30 September 2013

Accepted:

30 October 2013

Abstract

Lipases are biocatalyst having wide applications in industries due to their versatile properties. In the present study, a lipolytic bacterial strain, Bacillus subtilis BDG-8 was isolated from an oil based industrial soil. The effect of selenium and nickel as a media supplement on enhancement of lipase production, was studied individually with the isolated strain by varying the concentration of selected metal. 60?g l^-1 selenium enhanced lipase production to an enzyme activity measuring 7.8 U ml^-1 while 40 ?g l^-1 nickel gave the maximum enzyme activity equivalent to 7.5 U ml^-1. However, nickel and selenium together at a range of concentration with an equal w/v ratio, at 60 ?g l-1 each, showed the maximum lipase activity of 8.5 U ml^-1. The effect of pH and temperature on lipase production showed maximum enzyme activity in the presence of each of the metals at pH 7 and 35?C among the other tested ranges. After optimisation of the parameters such as metal concentration, pH and temperature lipase production by Bacillus subtilis BDG-8 had increased several folds. This preliminary investigation may consequently lead as to various industrial applications such as treatment of wastewater contaminated with metal or oil with simultaneous lipase production.

Key words

Bacillus subtilis, Enzyme activity, Lipase, Nickel, Selenium, Temperature

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