Efficient biodiesel production using a lipase@ZIF-67 nanobioreactor

A new heterogeneous bio-catalyst was synthesized by encapsulating lipase into the microporous zeolite imidazolate framework, ZIF-67, using a bottle-around-a-ship method. The enzyme/ZIF-67 association is higher than those resulting from post-synthetic approaches. The resulting biocomposite lipase@ZIF-67 was fully characterized by UV-vis and Fourier transform infrared (FT-IR) spectroscopies, powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FE-SEM), Thermal gravimetric analyses (TGA), N₂ adsorption–desorption and energy dispersive X-ray (EDX). The prepared bio-catalyst was successfully applied for transesterification of soybean oil to biodiesel in a solvent-free medium. The effect of different parameters, such as pH, temperature, molar ratio of methanol to oil and mass ratio of bio-catalyst to oil, was deeply investigated. Finally, the immobilized enzyme was reused during 6 cycles transesterification reaction without a significant decrease in its initial activity. This simple and efficient association procedure seems well-adapted to produce enzymatic bio-catalyst for biodiesel production.