Characterization of Commerical Lipase from Indigenous Fungal Strains and Biomass

Abstract

In this study, lipases were isolated from two locally screened fungal strains i.e. Aspergillus crevinus and Aspergillus niger, optimized statistically and purified via fractionation of ammonium sulfate and through Sephadex G-100 gel permeation chromatography. Lipases of A. crevinus and A. niger were 2.26-fold and 2.51-fold purified, having a specific activity of 223.60 U/mg and 233.66 U/mg, respectively. The molecular masses were estimated as 60 kDa for both strains by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The maximum lipase activities of both strains were shown at 4 % (W/V) alginate (ALG) and chitosan (CTS). The uniform size 2.0 ±0.25 mm diameter of chitosan-alginate (CTS-ALG) beads was developed by using ultrasonically dispersed 2.0 % (W/V) chitosan and alginate with 0.5 % (W/V) glutaraldehyde by means of macromolecular crosslinking agents. The detergent compatibility, leather dehairing purposes, removal of fat and grease, and estimation of triglyceride hydrolysis, various parameters were recorded .The effect of temperature, pH , substrate concentration, incubation period, modulators, activators and inhibitors, solvents, stabilizers, and surfactant on purified free (PF) lipase, CTSimmobilized, and combined CTS-ALG-immobilized lipase fractions, and reusability profile of CTS-immobilized lipase of both strains were investigated. The CTSimmobilized lipase fractions of both strains were optimally active and stable at temperature (30-55 °C) and pH (5-11). The stability of CTS-immobilized and CTSALG-immobilized lipases of both strains was increased as compared to PF lipase. Subsequently incubation for 75 min, CTS-ALG-LAC3 (chitosan-alginate lipase A. crevinus) retained > 95% activity at temperature 75 °C and pH 8.0, and CTS-ALG-LAN3 (chitosanalginate lipase A. niger) also retained >90 % activity at pH 9.0 and temperature 65 °C. The present work engrossed on the utilization of recently formed CTS-ALG immobilized lipases for industrial. It is suitable additive in detergents, rendering its latent candidature for tannery and leather industry.