An extracellular lipase of a newly isolated S. aureus strain ALA1 (SAL4) was purified from the optimized culture medium. The SAL4 specific activity determined at 60 °C and pH 12 by using olive oil emulsion or TC4, reached 7215 U/mg and 2484 U/mg, respectively. The 38 NH2-terminal amino acid sequence of the purified enzyme starting with two extra amino acid residues (LK) was similar to known staphylococcal lipase sequences. This novel lipase maintained almost 100% and 75% of its full activity in a pH range of 4.0-12 after a 24 h incubation or after 0.5 h treatment at 70 °C, respectively. Interestingly, SAL4 displayed appreciable stability toward oxidizing agents, anionic and non-ionic surfactants in addition to its compatibility with several commercial detergents. Overall, these interesting characteristics make this new lipase promising for its application in detergent industry.
Keywords: Characterization; Detergent-stable; HPLC, high-performance liquid chromatography; NaDC, sodium deoxycholic acid; NaTDC, sodium taurodeoxy cholic acid; OD, optical density; PCR, polymerase chain reaction; Purification; S. aureus, Staphylococcus aureus; SAL, Staphylococcus aureus lipase; SDS, sodium dodecyl sulfate; SEL, Staphylococcus epidermidis lipase; SHyL, Staphylococcus hyicus lipase; SL1, Staphylococcus sp. lipase; SSL, Staphylococcus simulans lipase; SXL, Staphylococcus xylosus lipase; Staphylococcus aureus lipase; TC18, triolein; TC3, tripropionin; TC4, tributryin; TC8, trioctanoin; TFA, tri fluoroacetic acid; Thermo-alkaline; rDNA, ribosomal deoxy ribo nucleic acid; rpm, revolutions per minute.