Incorporation of omega-3 polyunsaturated fatty acids into soybean lecithin: effect of amines and divalent cations on transesterification by lipases.

The transesterification of soybean lecithin with methyl esters of EPA and DHA in an organic solvent (hexane) using various commercially available lipases was studied. Lipases produced by Candida antarctica, Pseudomonas fluorescens, Burkholderia cepacia, Mucor miehei, Thermomyces lanuginosus and Rhizomucor miehei were compared, in the absence or presence of histidine, arginine, urea, Ca²⁺, Mg²⁺, or a combination of urea and divalent cations (additives at 5 % of the total lipid mass). Transesterification using the R. miehei enzyme reached 11.32 and 12.30 % in the presence of Ca²⁺ or Mg²⁺ respectively, and 8.58 and 9.31 % when urea was also added. These were the greatest degrees of transesterification obtained. The results suggest the potential use of this immobilized lipase as a catalyst for interesterification reactions in organic solvent systems with low water content.