Enzymatic Synthesis Of Cinnamate And Optimization

Researchers' interest had been aroused greatly by studying cinnamic acid ester compounds, which were one of the most important derivatives of cinnamic acid, due to their useful biological properties and physico-chemical properties(For instance, antioxidant, anti-inflammatory, anti-cancer, anti-ultraviolet radiation and anti-fungal activities). The enzymatic synthesis received more and more attention along with the improvement of social development and the increasing of human's environmental awareness. This essay studied the synthesis of cinnamic acid ester between of cinnamic acid and alcohol with immobilized lipase as catalyst and kinetics and thermodynamics of lipase-catalyzed synthesis of benzyl cinnamate.This essay includes four aspects. First, enzymatic esterification synthesis of ethyl cinnamate with immobilized lipase in organic solvent was studied. Compared with acetone, the convertion could be improved greatly when isooctane was used as reaction media. Besides, parameters such as water activity, lipase loading and substance mole ratio were researched and the optimum catalytic reaction conditions were then obtained.In second and third aspects,we synthesize benzyl cinnamate in organic solvent with cinnamic acid and benzyl alcohol, Lipozyme TLIM lipase as catalyst. The results showed that Lipozyme TLIM lipase was efficient for catalyzing the esterification of cinnamic acid compared to Novozym 435 lipase. Besides, the optimized process conditions were investigated by ‘one-factor-at-a-time' method and response surface methodology, respectively.In fourth aspect, kinetics and thermodynamics of lipase-catalyzed synthesis of benzyl cinnamate in isooctane were investigated. The results showed that Ping-Pong Bi-Bi mechanism having substrate(benzyl alcohol) inhibition was introduced to describe the enzymatic kinetics. Furthermore, the activation energy of the first-step reaction was higher than that of the second-step reaction, suggesting that the first-step reaction was the rate-limiting reaction and could be easily improved by enhancing temperature. At the same time, the thermodynamic parameters were estimated and showed that the enzymatic esterification of cinnamic acid was endothermic process and increasing in temperature will be advantageous to this reaction.