Purification and Optimization of Extracellular Lipase from a Novel Strain Y4.

The exogenous lipolytic activities of sp. have been recognized earlier but the genus further contains many more unexplored strains. In this study, the extracellular lipase activity of Y4 (GenBank accession no. MT773277), isolated from during our previous study, was regulated by different physicochemical parameters, such as pH, temperature, shaking speed, and incubation time. For efficient immobilization of the extracellular lipase, 4% sodium alginate, 50 mL of 25 nM CaCl.2HO solution, and 15 min. Hardening time of gel beads in calcium chloride was used. For the first time, . Y4 lipase was purified using ammonium sulphate precipitation followed by dialysis and DEAE-Sepharose anion exchange chromatography with Sepharose-6B gel filtration chromatography, yielding ∼15-fold purified lipase with a final yield of 96 U/mL. The SDS-PAGE of purified lipase displayed a single strong band, indicating a monomeric protein of 45 kDa. At a temperature of 35°C and pH 8, the purified lipase showed maximum hydrolytic activity. Using p-nitrophenyl acetate (p-NPA) as the hydrolysis substrate, the values of and derived from the Lineweaver-Burk plot were 4.625 mM and 125 mol/minmg, respectively.