Effects of different enzymes on the yield of CG
Enzyme is a critical factor on the esterification of CA with glycerol. Four kinds of enzyme including NOVOzyme 435, Lipozyme 435, Lipozyme TLIM and Lipozyme RMIM were used as the catalyst (loaded at 3 % (relative to the weight of total substrates)) in the esterification of CA with glycerol. In this experiment, the molar ratio of CA to glycerol was fixed at 1:150. Fig. 3 showed the yield of CG at 80 oC after the reaction time of 24 h. The yield of CG achieved with Lipozyme 435 was slightly higher than that of Novozyme 435, while much higher than those of Lipozyme TLIM and Lipozyme RMIM. Hence, Lipozyme 435 was chosen as the suitable catalyst.
Fig. 3. Effect of enzyme type on the yield of CG. Reaction conditions: the molar ratio of CA to glycerol 1:150, reaction temperature 80 oC, enzyme load 3 % (relative to the weight of total substrates), 86.7 kpa, 24 h.