Immobilization of Lipase in Reverse Micelles Via Sol-Gel Process

Enzyme immobilization technology is one of the hot topics in bio-chemical engineering area. In this study, Reverse micelle and sol-gel method had been integrated together to prepare the immobilized lipase via the encapsulation of the enzyme molecule in the “pool” form in the sodium bis-(2-ethyl 1-hexyl) sulfosuccinate (AOT) micelle system. The properties and stability of the immobilized lipase was studied as follows:

Isooctane and AOT were employed to construct the reverse micelle system to afford the "pool" for lipase immobilization. The lipase was successfully immobilized in the "pool" via sol-gel process and the activity of the immobilized lipase in reverse micelles could be determined by chromogenic method. The conditions for preparation of immobilized lipase had been optimized and list as follows: the pH value of the buffering system was 7.0; alkoxy silane precursor was Tetraethoxysilane (TEOS); content of TEOS in the buffering was 15% by volume. Molar ratio of surfactant to water (W₀) significantly influenced the activity of both free and immobilized lipase in the reverse micelles. The highest immobilized lipase activity was achieved when W₀ was set at 50 after the optimization. The comparison between the immobilized and free lipase in the reverse micelle was carried out, and results demonstrated that immobilized lipase possessed the better thermal stability, organic solvent resistance and storage stability than free lipase.

It was hopeful that our studies provide a new thought for the immobilization of enzyme which could be potentially used in the industrial application of lipase in the future.