title: An insight on acyl migration in solvent-free ethanolysis of model triglycerides using Novozym 435.
abstract: In this work, the ethanolysis of triglycerides catalyzed by immobilized lipase was studied, focusing on the secondary reaction of acyl migration. The catalytic tests were performed in a solvent-free reaction medium using Novozym 435 as biocatalyst. The selected experimental variables were biocatalyst loading (5-20mg), reaction time (30-90min), and chain length of the fatty acids in triglycerides with and without unsaturation (short (triacetin), medium (tricaprylin) and long (tripalmitin/triolein)). The formation of 2-monoglyceride by ethanolysis of triglycerides was favored by long reaction times and large biocatalyst loading with saturated short- to medium-chain triglycerides. In the case of long-chain triglycerides, the formation of this monoglyceride was widely limited by acyl migration. In turn, acyl migration increased the yield of ethyl esters and minimized the content of monoglycerides and diglycerides. Thus, the enzymatic synthesis of biodiesel was favored by long-chain triglycerides (which favor the acyl migration), long reaction times and large biocatalyst loading. The conversion of acylglycerides made from long-chain fatty acids with unsaturation was relatively low due to limitations in their access to the active site of the lipase.
authors.affiliation: Planta Piloto de Ingeniería Química (PLAPIQUI), Universidad Nacional del Sur, CONICET, Camino La Carrindanga Km 7, CC 717, 8000 Bahía Blanca, Argentina.
authors.forename: Daniel Alberto
authors.initials: DA
authors.lastname: Sánchez
authors.affiliation: Planta Piloto de Ingeniería Química (PLAPIQUI), Universidad Nacional del Sur, CONICET, Camino La Carrindanga Km 7, CC 717, 8000 Bahía Blanca, Argentina.
authors.forename: Gabriela Marta
authors.initials: GM
authors.lastname: Tonetto
authors.affiliation: Planta Piloto de Ingeniería Química (PLAPIQUI), Universidad Nacional del Sur, CONICET, Camino La Carrindanga Km 7, CC 717, 8000 Bahía Blanca, Argentina. Electronic address: mlferreira@plapiqui.edu.ar.
authors.forename: María Luján
authors.initials: ML
authors.lastname: Ferreira
mesh_terms: D056804:Biofuels; D002849:Chromatography, Gas / Q000379:methods; D004075:Diglycerides / Q000138:chemical synthesis / Q000737:chemistry; D004798:Enzymes / Q000737:chemistry; D004800:Enzymes, Immobilized / Q000737:chemistry; D004952:Esters / Q000138:chemical synthesis; D005019:Ethyl Ethers / Q000138:chemical synthesis / Q000737:chemistry; D005224:Fats, Unsaturated / Q000138:chemical synthesis / Q000737:chemistry; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism; D005656:Fungal Proteins; D005990:Glycerol / Q000138:chemical synthesis / Q000737:chemistry; D007700:Kinetics; D008049:Lipase / Q000737:chemistry* / Q000378:metabolism*; D008956:Models, Chemical; D050178:Monoglycerides / Q000138:chemical synthesis / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D014280:Triglycerides / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D056804:Biofuels; D004075:Diglycerides; D004798:Enzymes; D004800:Enzymes, Immobilized; D004952:Esters; D005019:Ethyl Ethers; D005224:Fats, Unsaturated; D005227:Fatty Acids; D005656:Fungal Proteins; D050178:Monoglycerides; D012997:Solvents; D014280:Triglycerides; C093667:Novozyme 435; D008049:Lipase; D005990:Glycerol
keywords: Acyl migration; Ethanolysis; Novozym 435; Triglycerides