Effect of reaction parameters on conversion of krill (Euphausia superba) oil by immobilized lipase ethanolysis Hye-youn Lee, A.S.M. Tanbirul Haque, Seon-Bong Kim, Yang-Bong Lee, Byung-Soo Chun * Department of Food Science and Technology, Pukyong National University, 45 Yongso-ro, Nam-Gu, Busan 608-737, Republic of Korea 1. Introduction Antarctic krill (Euphausia superba), with an estimated biomass of 125–725 million tones and with its ecological role as the most important trophic link between primary production and verte- brate predators, is incontestably the keystone species in the Antarctic marine ecosystem. Antarctic krill is a rich source of polyunsaturated fatty acids (PUFAs), mainly the long-chain omega-3 fatty acids eicosapentaenoic acid (EPA, C 20:5 n-3) and docosahexaenoic acid (DHA, C 22:5), which have been attracted much attention for health benefits. In addition, v-3 fatty acids are essential for normal growth and development of the brain and the nervous system and may also play an important role in the prevention and treatment of coronary artery disease, hypertension, arthritis, others inflammatory and autoimmune disorders and cancer. It has been proved that the commercial value of fats and oils depends not only on fatty acid compositions of triglyceride but also on the distribution of fatty acids on the glycerol [1]. Manufacturing lipid products from natural resources normally yields significant amounts of low-value fats and oils next to the focused high valued processes [2,3]. It can enhance the value and the applicability of oils in various methods; hydrolysis, esterification, acidolysis and modification of fats and oil. The chemically catalyzed reaction of lipids with alcohols is simple to carry out, but can generate many side products like soaps and free fatty acids which can be tedious to remove from the reaction mixture [4]. The use of lipase is more selective and ideally leads only to monoglycerides and fatty acid esters [5,6]. In a several research on lipase-catalyzed synthesis of symmetrical triacylglycerol reported that the immobilized lipases exhibit very efficient catalytic activity in the ethanolysis [7–9]. Conventional methods based on solvent extraction from natural matrices are time-consuming as they involve a multiple often expensive and potentially hazardous. Decomposition or degradation of thermo labile compounds cannot be avoided in a conventional extraction method, since relatively high temperatures are required for these processes. Organic solvents are also harmful to human health as well as the environment. In recent years, supercritical fluid extraction technology (SFE) which is used as an alternative for lipid extraction to organic solvent extraction has received much attention, because it allows a reduction in extraction time, requires little sample manipulation, and involves a much lower solvent consumption, leading to extracts of increased purity. The effects of pressure on enzymatic-catalyzed reactions have been presented by Erickson et al. [10]. Steytler et al. [11] reported that an increase in the esterification rate using lipases in near critical region when pressure was increased. The observed pressure effect was attributed to a higher adsorption of the synthesized ester to the enzyme at the lower pressures. Compared with other gases, CO 2 has been the most widely studied fluid as solvent medium for enzyme-catalyzed reaction [12]. The lipase is employed in immobilized form because it would allow the re- utilization of the enzyme in continuous process that reduces the production cost [13]. Journal of Industrial and Engineering Chemistry 20 (2014) 1097–1102 A R T I C L E I N F O Article history: Received 4 April 2013 Accepted 28 June 2013 Available online 10 July 2013 Keywords: Monoglyceride Diglyceride Ethanolysis Immobilized lipase Krill oil A B S T R A C T Monoglyceride and diglyceride were produced by performing ethanolysis of krill oil with immobilized lipase and the influence of various parameters on the enzymatic ethanolysis was assessed. As an immobilized lipase, lipozyme TL-IM (thermonuces lanuginose) was used. Ethanolysis was done in non- pressurized and pressurized system to compare the reaction rate and yield. The optimal condition was found at 2.0 of ethanol mole ratio, temperature of 60 8C, lipases amount of 5 wt% in non-pressurized system. At pressurized system the optimal temperature and pressure was found at 50 8C and 10 MPa. However, at 50 8C monoglyceride was higher in pressurized system than in non-pressurized system. ß 2013 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved. * Corresponding author. Tel.: +82 51 629 5830; fax: +82 51 629 5824. E-mail addresses: bschun@pknu.ac.kr, jonyasad2005@yahoo.com (B.-S. Chun). Contents lists available at SciVerse ScienceDirect Journal of Industrial and Engineering Chemistry jou r n al h o mep ag e: w ww .elsevier .co m /loc ate/jiec 1226-086X/$ – see front matter ß 2013 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.jiec.2013.06.047