Insight into microwave irradiation and enzyme catalysis in enantioselective resolution of DL-(±)-3-phenyllactic acid.
Lipase catalyzed kinetic resolution of DL-(±)-3-phenyllactic acid (DL-(±)-3-PLA) was investigated to study the synergistic effect of microwave irradiation and enzyme catalysis. Lipases from different sources were employed for the transesterification of DL-(±)-3-PLA under otherwise similar conditions, among which Novozyme 435 efficiently catalyzed the resolution of DL-(±)-3-PLA to L-(-)-O-acetyl-3-PLA using vinyl acetate as the acyl donor, showing excellent conversion (49%) and enantiomeric excess (>99%). The effect of various parameters affecting the initial rate, conversion and enantiomeric excess of the reaction were studied to establish kinetics and mechanism. There is a synergism between enzyme catalysis and microwave irradiation; an increase in initial rates up to 1.8-fold was observed under microwave irradiation than that under conventional heating. The analysis of initial rate data showed that reaction obeys ternary complex (ordered bi-bi) mechanism with inhibition by DL-(±)-3-PLA. The calculated and simulated rates match very well showing the validity of the proposed kinetic model.
Department of Chemical Engineering, Institute of Chemical Technology, Matunga, Mumbai 400 019, India. gdyadav@yahoo.com
Ganapati D
GD
Yadav
Sandip V
SV
Pawar
D004800:Enzymes, Immobilized / Q000378:metabolism*; D007700:Kinetics; D007773:Lactates / Q000378:metabolism*; D008049:Lipase / Q000378:metabolism*; D008872:Microwaves
D004800:Enzymes, Immobilized; D007773:Lactates; C017648:3-phenyllactic acid; D008049:Lipase