Enzymatic esterification of fatty acid esters by tetraethylammonium amino acid ionic liquids-coated Candida rugosa lipase

Enzymatic production of fatty acid esters from the esterification of oleyl alcohol with various fatty acids was investigated by using two new tetraethylammonium amino acid ionic liquids-coated Candida rugosa lipase (ILs-CRL) as biocatalysts in hexane. Both enzyme derivatives were prepared by mixing Candida rugosa lipase with tetraethylammonium l-histidinate (IL1) and tetraethylammonium l-asparaginate (IL2). The ILs-CRL system containing the equivalent protein concentration as in CRL showed higher esterification activity especially on medium chain fatty acids (C12–C16) as compared to non-coated CRL. Hydrophilicity of ILs may play an important role in hydrogen bonding with enzyme surface and consequently stabilize the ILs-CRL.