Somaye Imanparast - Department of Biotechnology, Iranian Research Organization for Science and Technology, Tehran, Iran
Javad Hamedi - Department of Microbial Biotechnology, School of Biology, College of Science, University of Tehran, Tehran, Iran
Mohammad Ali Faramarzi - Department of Pharmaceutical Biotechnology, Faculty of Pharmacy and Biotechnology Research Center, Tehran University of Medical Sciences, Tehran, Iran

Background and Aim : Polyunsaturated fatty acids (PUFA) are essential in human nutrition since they play an important role in the prevention of several diseases. The enzymatic esterification using solvent tolerant lipase has become an attractive approach for polyunsaturated acylglyserols production. The aim of this study is immobilization of a solvent tolerant lipase for enzymatic improvement of n۶/n۳ ratio in PUFAs from flaxseed oil.Methods : Solvent tolerant lipase obtained from Actinomadura sediminis UTMC ۲۸۷۰ was immobilized by incubating ۱۵۰ U of the enzyme per gram of the carrier in phosphate buffer (۵۰ mM, pH ۷.۴) and stirring at ۲۵ °C for ۴۵ min. Enzymatic synthesis of AGs rich in n-۳ PUFAs was divided into four main stages: (i) the extraction of FFAs from flaxseed oil, (ii) PUFA concentration, (iii) enzymatic esterification, and (iv) GC analysis. The reusability of the immobilized lipase was evaluated by measuring the recycling efficiency in sequential reaction cycles until the enzyme activity was markedly reduced.Results : GC analysis of fatty acid composition revealed that the product contain ۵۰ % w/w of PUFA including ۴۲ % w/w α-linolenic (ALA, ۱۸:۳, n-۳) and ۹.۷ % w/w linoleic acid (LA, ۱۸:۲, n-۶). Value of n-۶/n-۳ ratio of the product with ۰.۲۴ was comparable to cod liver, Herring, Salmon, and Sardine oils with n-۶/n-۳ ratio of ۰.۰۴, ۱.۰۱, ۰.۰۳, and ۰.۰۷ respectively and it showed remarkably different with seed oils showing high value of n-۶/n-۳ ratio. Conclusion : Due to the high efficiency of the enzyme to n-۳ PUFA, specifically in present organic solvent, lipase from A. sediminis can be suggested as an ideal alternative in the production of omega-۳ concentrates in their natural form.

Immobilization, Polyunsaturated fatty acids, Solvent tolerant lipase