Transesterification reaction using Staphylococcus haemolyticus L62 lipase crosslinked on magnetic microparticles

• Lipase L62 was immobilized onto magnetic particles by enzyme precipitate method.
• L62-AMP showed higher optimum temperature and broader pH stability than free lipase.
• L62-AMP performed one-step transesterification reaction using high methanol content.

Staphylococcus haemolyticus L62 lipase is methanol-stable enzyme and its functional expression has been performed in Escherichia coli cells. The recombinant lipase L62 was immobilized on amine-magnetic microparticles (AMPs) by protein precipitation and covalent cross-linking methods. The physical properties of L62-AMP were evaluated by electron microscopy, a zeta potential system, and magnetic property measurement system. L62-AMPs had diameters of about a 1.6 μm size and displayed a saturation magnetic value of 25.56 A m2/kg. In comparison with free lipase L62, L62-AMP showed high optimum temperature and high activity at a wide pH range. L62-AMP showed high hydrolytic activity toward tributyrin and olive oil among various triglycerides. L62-AMP was recovered within 2 min with Neodymium magnet and maintained >90% residual activity after 4 recoveries. L62-AMP was used to produce fatty acid methyl ester (FAME) using methanol and olive oil with molar ratio of 6:1. By one step-transesterification reaction, the yield of FAME was about 86.4% after a 24 h reaction at 30 °C.

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