Isolation and Characterization of Pseudomonas sp. KLB1 Lipase from High Fat Wastewater

Abstract

Six isolates of lipase-producing micro-organisms were screened from two types of wastewater. The bacterial isolates were KLB1, KLB2, KLB3 and isolated yeasts were KLY1, KLY2 and KLY3. The isolate showed highest lipase activity was KLB1 which later was identified as Pseudomonas sp. Lipase
of Pseudomonas sp. KLB1 was found to be an inducible enzyme with palmolein. The model for lipase production was growth associate pattern. As regards to the physicochemical properties, the Pseudomonas sp. KLB1 lipase had maximal activity at 50°C and pH 9. For its stability, even though this enzyme showed the maximal stability at pH 7.0 and 37°C, its stability was increased when incubated at pH 8.0-10 and 37, 50, 60, and 70°C. The residue activity was 76% and 76.23% at pH 10, 70°C and pH 9, 37°C. However, the lipase showed two pH stability ranges that possible indicated two types of lipases were formed in Pseudomonas sp. KLB1. The lipase was activated by Ca²⁺, K⁺,and Na⁺, (NH₄)₂S₂O₃ and ascorbic acid but inhibited by Zn²⁺, Mn²⁺, Co²⁺, KI and EDTA. The enzyme is also more specific on the medium and long chain triacylglycerol of vegetable oil than of animal fat. The Km and Vmax of tributyrin hydrolysis were 110.9 mM, and 2.45 mM s^-1, respectively whereas these kinetic parameters from palmplein hydrolysis were 1,188.8 mM, and 5.25 mM s^-1, respectively.