Response surface optimisation of lipase-catalysed esterification of glycerol and n-3 polyunsaturated fatty acids from salmon oil

Enzymatic synthesis of acylglycerols from glycerol and n-3 fatty acid concentrate, prepared from salmon oil, was optimised by response surface methodology (RSM). Salmon oil was hydrolysed using a stereospecific sn-1, sn-3 lipase from Aspergillus oryzae and filtered on hydrophobic membrane. Acylglycerols synthesis was performed using Lipozyme IM (Novo Nordisk) under different reaction conditions according to a Doehlert experimental design. Effects of temperature, water content, glycerol/fatty acid molar ratio, and enzyme/substrate ratio were studied. Pathway maximisation indicated that an esterification degree of 97% was obtained under the following conditions: glycerol/oil 1.2, temperature 46 °C, molecular sieves 3.5 g per 100 ml and enzyme/substrate 8.1.