Purification and characterization of an organic solvent-tolerant and detergent-stable lipase from Haloferax mediterranei CNCMM 50101

The present study investigates the purification and biochemical characterization of an extracellular lipase (HML) from Haloarchaea Haloferax mediterranei strain ATS1, isolated from the Sebkha (Medea, Algeria). The pure protein was obtained with ammonium sulfate precipitation (40-70%)-dialysis and UNO Q-6 FPLC, and characterized biochemically. Matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/MS) analysis revealed that the purified enzyme was a monomer, with a molecular mass of 45,011.09 Da. It showed optimum lipase activity at pH 7 and 60 °C. HML showed a higher specific activity on triacylglycerols with long-chains fatty acids, indicating that HML is a true lipase. This enzyme was completely inhibited by phenylmethanesulfonyl fluoride (PMSF) and diiodopropyl fluorophosphates (DFP), which suggested its belonging to the serine lipase family. The K_m and V_max for HML toward olive oil were 1.01 mM and 1195 U/mg, respectively. Compared to Lipolase, HML displayed an elevated organic solvent tolerance, an outstanding stability to surfactants, oxidizing, and auxiliary agents, a considerable compatibility with various commercialized laundry detergents, and wash performance analysis revealed that it could remove oil-stains effectively. Overall, HML has a number of attractive properties that make it a potential promising candidate for the synthesis of non-aqueous peptides and detergent formulations.