Fructose stearate esterify in packed bed reactor using immobilized lipase.

Abstract

The enzymatic esterification of sugar-fatty acid ester to produce bio-based surfactants or emulsifiers has been recognized as an alternative way to the chemical synthesis due to its environmentally friendly reaction. Therefore, present study aimed to employ an optimal procedure for the continuous synthesis of fructose stearate by using immobilised Rhizomucor miehei lipase (RML) in a packed-bed reactor. Briefly, lipase immobilization on chicken eggshells was conducted and characterized using Transmission Electron Microscopy (TEM) and Brunauer-Emmett-Teller (BET) analysis. Subsequently, the screening of enzyme loading was performed. Response Surface Methodology (RSM) based on central composite design (CCD) was applied to optimize the temperature, flow rate and substrate molar ratio. The immobilisation efficiency on eggshells was 63.64%. After immobilization, the BET surface area, total pore volume and pore diameter of the eggshells were reduced to 1.0714 m2/g, 1.003 x 10−3 cm3/g and 3.7449 nm, respectively. Furthermore, both BET analysis before and after immobilization revealed that the pore structures of eggshells were classified as Type II isotherm. From preliminary study, enzyme loading of 1.5 g immobilized lipase was selected as the optimum enzyme loading. The quadratic model in RSM analysis was validated to predict the optimum conditions. A maximum of fructose stearate concentration as high as 7.252 x 10−1 mol/L obtained at a better condition of 37.47°C under a flow rate of 0.074 ml/min and 2.82:1 substrate molar ratio of fructose to stearic acid. This work has pronounced the eggshell is as a potential carrier for RML immobilization with ability to be used in packed bed reactor to synthesis fructose stearate.