Glycerolysis of sardine oil catalyzed by a water dependent lipase in different tert-alcohols as reaction medium

Abstract

SUMMARY:The production of monoacylglycerol rich in polyunsaturated fatty acids (PUFA) via enzymatic glycerolysis of sardine oil in a homogeneous system was evaluated. Reactions were conducted in two different tert-alcohols. Based on the phase equilibrium data, the amount of solvent added to create a homogeneous system has been calculated and optimized. The immobilized lipase used in this work was Lipozyme RM IM from Rhizomucor miehei, a water dependent lipase. The amount of water added as well as other reaction parameters were studied to evaluate the optimum conditions for monoacylglycerol obtencion. An initial reactant mole ratio glycerol to sardine oil 3:1, 12 wt% of water based on glycerol content and 10 wt% of lipase loading (based on weight of reactants), achieved a MAG yield of around 70%, with nearly 28 wt% PUFA, with low free fatty acid content (lower than 18 wt%).KEYWORDS: Fish oil; Glycerolysis; Lipase; Monoacylglycerol; Rhizomucor miehei; Tert-alcohols RESUMEN: Glicerolisis de aceite de sardina catalizada por una lipasa dependiente de agua en diferentes tert-alcoholes como medio de reacción. En este trabajo se ha estudiado la producción de monoacilglicéridos, ricos en ácidos grasos poliinsaturados (AGPI), mediante glicerolisis enzimática de aceite de sardina. La reacción se ha llevado a cabo en dos tert-alcoholes para conseguir de esta forma un medio homogéneo de reacción. La cantidad de disolvente añadida al medio de reacción se ha optimizado y calculado en base al equilibrio de fases de los componentes del sistema. La lipasa empleada como biocatalizador ha sido la enzima inmovilizada Lipozyme RM IM de Rhizomucor miehei, una lipasa dependiente de agua. Se ha estudiado el efecto de distintos parámetros cinéticos, así como de la cantidad de agua añadida al medio de reacción, en la producción de monoacilglicéridos. De los resultados obtenidos, se puede concluir que, para una relación molar inicial de reactantes glicerol:aceite de sardina de 3:1, un 12 % en peso de agua en base al glicerol y un 10 % en peso de lipasa, en base al peso de reactantes; se puede llegar a conseguir un rendimiento en monoacilglicéridos alrededor del 70 % en peso, con casi un 28 % en peso de AGPI y un bajo contenido en ácidos grasos libres (menor del 18 % en peso).

Enzymatic Glycerolysis of Palm Kernel Olein-Stearin Blend for Monolaurin Synthesis as an Emulsifier and Antibacterial

“…During glycerolysis reactions, the majority of the glycerol reacted with fatty acids derived from TAG to produce monoacylglycerol [ 20 ]. Theoretically, the stoichiometry of the glycerolysis reaction requires a glycerol to fat (oil) molar ratio of 1:2 to provide 3 moles of MAG during this process [ 17 , 21 ]. However, the yield of monoacylglycerol depends on the equilibrium conditions, due to several factors [ 22 ].…”

“…In this reaction, MAG and DAG were high based on the excess and limited use of glycerol, respectively [ 24 ]. According to the equilibrium law, an increase in the glycerol content shifted the balance towards the production of MAG [ 21 ] and a molar ratio of oil to glycerol of 1:4 was selected for further experiments.…”

Supercritical CO2 processing of omega-3 polyunsaturated fatty acids – Towards a biorefinery for fish waste valorization

“…Other food-grade alcohols such as glycerol can be also used as acyl donors in enzymatic alcoholysis of fish oil [78,79]. This approach is particularly advantageous because the more bioavailable and stable 2-MAGs can be obtained in a one-step reaction, although it is limited by the poor miscibility of the substrates [78].…”

“…Other food-grade alcohols such as glycerol can be also used as acyl donors in enzymatic alcoholysis of fish oil [78,79]. This approach is particularly advantageous because the more bioavailable and stable 2-MAGs can be obtained in a one-step reaction, although it is limited by the poor miscibility of the substrates [78]. To overcome this drawback, organic solvents such as tertiary alcohols [77][78][79][80][81], and/or surfactant-stabilized emulsions [82] can be used in order to achieve homogeneous reaction systems.…”