title: Evaluation and modelling the utility of SCCO2 to support efficient lipase mediated esterification.
abstract: Supercritical fluids offer environmental advantages over chemical solvents, while providing enhanced separation and chemical selectivity. The use of supercritical fluids for the recovery of products from biomass and the transformation of selected molecules (to add value) was studied. Free fatty acids were bio-catalytically transformed to fatty acid esters using lipase within a supercritical fluid environment. A central composite rotatable design was used to evaluate the influence of operating conditions on the enzymatic esterification process and a response surface equation was optimized to identify the most favourable process conditions for maximum free fatty acid conversion. Based on the model equation the process conditions under which it was predicted a yield of 100% esters could be obtained were: pressure 200 bar, temperature 60 °C, ethanol concentration 2.0 M, enzyme concentration 11 wt.% and time 60 min. Experiments conducted under these conditions gave an ester yield of 94.3% (close to predicted results). The activity per unit mass of biocatalyst was found to be 1585 μmol/min/g(cat). The results support the use of supercritical fluids for process integration.
authors: School of Chemical Engineering, University of Birmingham, Edgbaston, B15 2TT Birmingham, United Kingdom. m.n.baig@bham.ac.uk
authors: M N
authors: MN
authors: Baig
authors: R C D
authors: RC
authors: Santos
authors: C
authors: C
authors: Zetzl
authors: J
authors: J
authors: King
authors: D
authors: D
authors: Pioch
authors: S
authors: S
authors: Bowra
mesh_terms: D001203:Ascomycota / Q000201:enzymology*; D055162:Biocatalysis; D001709:Biotechnology / Q000379:methods; D002245:Carbon Dioxide / Q000378:metabolism*; D003627:Data Interpretation, Statistical; D004800:Enzymes, Immobilized / Q000378:metabolism; D004951:Esterification; D005227:Fatty Acids / Q000378:metabolism; D008049:Lipase / Q000378:metabolism*; D015233:Models, Statistical; D019301:Oleic Acid / Q000737:chemistry / Q000378:metabolism*
chemical_list: D004800:Enzymes, Immobilized; D005227:Fatty Acids; D002245:Carbon Dioxide; D019301:Oleic Acid; D008049:Lipase