The ��Lack of Fit F-value�� of 0.43 implies that lack of fit is not significant relative to pure error. Thus, it is possible quantitatively judge if the model represents the kinase inhibitor Dovitinib observations satisfactorily.Table 5ANOVA for the quadratic model developed for synthesis of TEA-based esterquat.3.3. Mutual Effect of Process ParametersThe terms in (2) show that interactions between variables have significant effect on the conversion% of enzymatic reaction of TEA-based esterquat. Therefore, instead of studying single variable the interactions will be investigated, which is significant and important for a comprehensive optimization study. Figure 2(a) shows the effects of different reaction time and agitation speed on the conversion % of product in three-dimensional surface response.

Generally, increased reaction time and agitation speed resulted in an increase percentage of conversion until agitation speed reached 523r.p.m. The response started to decrease after the agitation speed exceeded 523r.p.m. even at the higher reaction time. However, it was observed that reaction time showed a significant effect to the reaction conversion at the higher agitation speed. Increasing agitation speed had increased the external mass transfer rates between the bulk phase of the reaction mixture and surface of enzyme; moreover, higher reaction time also promoted collision time between enzyme and substrate molecules. As shown in Figure 2(b), the reaction with the enzyme amount of 5.80%w/w led to the maximum percentage of conversion.

Response surface plot for interaction between enzyme amount and reaction temperature was generated with reaction time fixed at 16h, the molar ratio of substrates (OA:TEA) 2:1 mole, and agitation speed 400r.p.m. The percentage conversion of product increased by increase ongoing from 3 to 5.80%w/w and thereafter decreased with further increase to 7%w/w. However, higher temperatures tended to induce enzyme inactivation due to denaturation processes [22, 23]. These results were similar to those in most reviewed papers, namely, that Novozym 435 was optimally used at temperatures between 40��C and 60��C [24, 25]. Figure 2(c) represents the effect of varying amount of enzyme and agitation speed on the synthesis of TEA-based esterquat with constant condition for other independent variables (reaction temperature of 60��C, reaction time of 16h, and substrate molar ratio of 2:1 mole).

From Figure 2(c), while the enzyme amount and agitation speed increased, the conversion of esterquat was increased as the agitation speed reached 523r.p.m. in the enzyme amount of 5.80%w/w. However, the effect of enzyme amount variable was lower than the effect Cilengitide of agitation speed variable. Increase in agitation speed caused the substantial increase in the specific interfacial area between the substrate and the enzyme present in the nonaqueous phase by reducing the droplet size [26, 27].