Insight into Microwave-Assisted Lipase Catalyzed Synthesis of Geranyl Cinnamate: Optimization and Kinetic Modeling
Cinnamate esters have gained importance due to their unique antioxidant, flavor, and fragrance properties. Synergism of microwave irradiation and enzyme catalysis was investigated in transesterification of ethyl cinnamate and geraniol. Effects of different operating parameters such as biocatalyst, solvent, and temperature were first studied. An increase in initial rates up to 4.2-fold was observed under microwave irradiation vis-a-vis conventional heating. Further, the Taguchi L16 (4*4) orthogonal array design with four level-four variables and 16 run was employed for the optimization of parameters including enzyme loading, temperature, speed of agitation, and substrate mole ratio. Optimal conditions obtained via the Taguchi approach were as follows: enzyme loading, 60 mg; temperature, 65 °C; speed of agitation, 300 rpm; and substrate mole ratio, 1:2. The analysis of initial rate data established the validity of the ternary complex ordered bi–bi mechanism with inhibition by geraniol. The experimental data fitted very well with the model predictions.
KeywordsGeranyl cinnamate Heterogeneous biocatalysis Transesterification Microwave irradiation Optimization Kinetic parameters
GDY received support from R.T. Mody Distinguished Professor Endowment and J. C. Bose National Fellowship of Department of Science and Technology, Government of India. SDS received SRF from UGC under its Meritorious Fellowship BSR program (CAS in Chemical Engineering Department). The authors thank Novo Nordisk, Denmark for the gifts of enzyme.
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