Efficient biocatalyst by encapsulating lipase into nanoporous gold

Xiaoyu Du,Xia Wang,Xueying Liu,Chao Wu,Yufei Li,Ping Xu

doi:10.1186/1556-276x-8-180

Abstract

Lipases are one of the most important biocatalysts for biotechnological applications. Immobilization is an efficient method to increase the stability and reusability of lipases. In this study, nanoporous gold (NPG), a new kind of nanoporous material with tunable porosity and excellent biocompatibility, was employed as an effective support for lipase immobilization. The pore size of NPG and adsorption time played key roles in the construction of lipase-NPG biocomposites. The morphology and composition of NPG before and after lipase loading are verified using a scanning electron microscope, equipped with an energy-dispersive X-ray spectrometer. The resulting lipase-NPG biocomposites exhibited excellent catalytic activity and remarkable reusability. The catalytic activity of the lipase-NPG biocomposite with a pore size of 35 nm had no decrease after ten recycles. Besides, the lipase-NPG biocomposite exhibited high catalytic activity in a broader pH range and higher temperature than that of free lipase. In addition, the leaching of lipase from NPG could be prevented by matching the protein’s diameter and pore size. Thus, the encapsulation of enzymes within NPG is quite useful for establishing new functions and will have wide applications for different chemical processes.

Highlights

Immobilization of enzymes on insoluble supports is a significant process due to its promising potential in improving enzyme thermal or pH stability, easing product purification, and facilitating enzyme recycling [1,2]
nanoporous gold (NPG), fabricated by a simple dealloying method, possesses the following unique properties: (1) it is a bulky material with microstructure, which means it can be employed and recovered; (2) it has an open three-dimensional structure while possessing a comparably high surface area, which favors strong adsorption and can afford high enzyme loading; (3) the pore size is tunable in a wide range from a few nanometers to many microns, which fits for a wide range of enzyme molecules with specific molecular
energy-dispersive X-ray spectrometer (EDS) analysis confirmed the existence of dominant elements such as C, N, and O (Figure 1D), providing a primary evidence of successful lipase immobilization on NPG

Summary

Introduction

Immobilization of enzymes on insoluble supports is a significant process due to its promising potential in improving enzyme thermal or pH stability, easing product purification, and facilitating enzyme recycling [1,2]. It is revealed that the pore size of NPG and adsorption time play significant roles in enzyme loading, leaching, activity, and reusability. Catalytic activity of lipase-NPG biocomposites For the immobilization of lipase, the suitability of NPG with pore sizes of 35 and 100 nm was investigated, respectively.

Results

Conclusion