Hydrodynamics and kinetics of lipase-catalysed synthesis of diacylglycerols (dag) in batch and continuous flow systems

• Main Author: Binti Abd Razak, Nurul Nadiah
• Other Authors: Laboratoire de Génie Chimique (LGC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Institut National Polytechnique de Toulouse - INPT, Sunway University, Patrick Cognet, Yolande Peres-Lucchese
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: HAL CCSD 2022
• Subjects: Diacylglycerol; Green catalyst; Candida antartica lipase B; Process intensification; Enzyme kinetis; Diacylglycérols; Catalyseur vert; Intensification des procédés; Cinétique enzymatique; [SDV.SA]Life Sciences [q-bio]/Agricultural sciences; antartic*
• Online Access: https://theses.hal.science/tel-04548472; https://theses.hal.science/tel-04548472/document; https://theses.hal.science/tel-04548472/file/BINTI_ABD_RAZAK1.pdf

Diacylglycerols (DAG) have been extensively used in food, medicine, cosmetic and pharmaceutical industries due to their outstanding properties as emulsifiers, stabilizers and nutritional benefits to human. To circumvent the use of chemical catalysts, this study investigated the synthesis of glycerol dioleates (GDO) through esterification of glycerol with oleic acid by Candida antartica lipase B (CALB 1) in the batch and continuous flow systems. The first section of this work examined the effects of different solvent systems on conversion, yield, and selectivity of glycerol oleates. The rheological properties of solventless, acetone, tert-butanol, and blended solvents systems exhibited Newtonian flow behavior, and their viscosities decreased at elevated temperatures. As compared to glycerol monooleates (GMO) and glycerol trioleate (GTO), GDO synthesis showed the highest yield (70%) and selectivity (54%) achieved at 40ºC within 2 h in the mixed solvents of acetone:tert-butanol at an enzyme load of 0.15 g. The second section focused on the optimization and kinetics of lipase-catalyzed synthesis of GDO using a batch reactor. A high oleic acid conversion of 73% and GDO selectivity of 77% were obtained in acetone: tert-butanol 70:30 (v/v) mixture at 45°C and an enzyme load of 0.15 g. At 45°C, the Ping-Pong Bi–Bi kinetic model with no substrate inhibition gives the best fit with parameter values of Vmax = 1.21 M h-¹, K Gm = 1.81 M and K OAm = 6.81 M, for glycerol and oleic acid concentrations between 0.31 to 1.32 M and 1.88 to 2.13 M, respectively. The final section studied the enzymatic synthesis of GDO under a continuous flow system. The maximum oleic acid conversion and GDO selectivity were achieved at 85% and 74% respectively, at 77 min of residence time (2x10-5 L min-¹) with 1.6:1 molar ratio of oleic acid:glycerol at a fixed temperature of 45ºC. The GDO content started to decrease after the water content reached 5%. Hydrodynamic studies showed that the esterification reaction is kinetically controlled and ...