Enzymatic Synthesis of Bio-Surfactant Fructose Oleic Ester Using Immobilized Lipase on Modified Hydrophobic Matrix in Fluidized Bed Reactor

Abstract

Enzymatic synthesis of fructose oleic ester (FOE) in stirred tank reactor using the immobilized lipase may cause a physical damage of support matrix, which causes a leaching of lipase from matrix. The objective of this research was to evaluate the best condition of FOE synthesis in fluidized bed reactor (FBR) using the immobilized lipase on modified hydrophobic matrix. Surface of Amberlite IRA 96 was modified with 2-phenylpropionaldehyde to obtain hydrophobic surface. Candida rugosa lipase was immobilized on the modified matrix. Subsequently, it was used for FOE synthesis in FBR system. Factors, such as reaction time, substrate flow rate, amount of water adsorbent, and substrate molar ratio were evaluated based on the conversion of oleic acid into FOE. Results from FTIR analysis showed that modified matrix had a peak at a specific wavelength ∼1674 cm^-1. It indicated that a group of imine (-C=N-) occurred after surface modification. The highest adsorption of lipase was obtained after adsorption for 45 min (13.28±0.57 mg lipase/g matrix), which was equivalent to 52.95±1.67%. The lipase activity was 73.66±5.35 U/g matrix. The best FOE synthesis condition was obtained at flow rate of 0.4 mL/min, molecular sieve of 12%, substrate molar ratio (fructose: oleic acid) 1:4 for 48 h. FOE was confirmed by TLC and FT-IR analysis, which they had Rf 0.72 and specific wave number of ∼1712 cm^-1, respectively. FOE had emulsion capacity, emulsion stability, droplet size, and HLB value of 92.83±0.46%; 85.65±0.92%; 7.86±0.93 μm; 11-16, respectively. Emulsion type of FOE was oil in water emulsion.