Alkaline thermostable cold active lipase from halotolerant <em> Pseudomonas</em> sp. VITCLP4 as detergent additive

Abstract

Extracellular cold active lipase from a novel strain of <em>Pseudomonas </em> sp. VITCLP4 was partially purified and characterized. The molecular mass was determined to be approximately 52 kDa by SDS-PAGE. Enzyme retained 80% of activity at 15^oC and 20^oC and 50% at 10^oC. It was stable at alkaline pH of 8-10 and in the temperature range of 30-40^oC Optimum pH was 8 and optimum temperature was 25^oC. The enzyme exhibited good stability in high and non polar solvents. Ca²⁺, Fe²⁺, Na⁺, Co²⁺ and Ba²⁺ ions enhanced the activity whereas Ni²⁺ and Hg⁺ ions were inhibitory. It was stable in presence of anionic, non-ionic detergents and the mild oxidant, sodium perborate. Enzyme activity was not inhibited by phenylmethylsulfonyl fluoride (PMSF), 2-mercaptoethanol, dithiothreitol (DTT), ehylenediaminetetraacetic acid (EDTA and Pepstatin-A. The enzyme preferentially hydrolyzed medium to high acyl chain length <em>p</em>-nitrophenyl esters. The <em>Km</em> and <em>Vmax </em> values as calculated by Lineweaver–Burk plot were 79.36 mM and 5.71 mM min^-1. Several properties of the enzyme favored its application as a detergent additive. Its efficacy in the removal of olive oil from cotton fabric along with various synthetic and commercial detergent formulations was assessed. Lipase had enhanced the oil removal upto 15%.