Optimization of reaction conditions for enzymatic synthesis of palm fatty hydrazides using response surface methodology.

Optimization of the enzymatic synthesis of palm fatty hydrazide by the response surface methodology (RSM) was conducted using the Design-Expert 6 software. The palm fatty hydrazide was synthesized from refined, bleached and deodorized palm olein (RBDPOo) and neutralized hydrazine monohydrate in the presence of Rhizomucor miehei lipase, Lipozyme RMIM, an immobilized lipase in n-hexane. The reaction conditions such as the percentage of enzyme, reaction temperature, stirring speed and reaction time were selected as independent variables or studied factors, while the amount of crude palm fatty hydrazide obtained was selected as a dependent variable or response. The study was conducted using a central composite design (CCD) at five coded levels and the experimental data were analyzed using a quadratic model. The analysis of variance (ANOVA) indicates that the model was significant at 95% confidence level with Prob>F of 0.0033, where the regression coefficient value, R² was 0.8415 and lack-of-fit of 0.0984. A percentage of enzyme of 6%, a reaction temperature of 40°C, a stirring speed of 350 rpm and a reaction time of 18 h were found to be the optimum conditions for the conversion of RBDPOo into palm fatty hydrazide.