Immobilizing Penicillin G Acylase Using Silica-Supported Ionic Liquids: The Effects of Ionic Liquid Loadings

Abstract

The supported ionic liquids (SILs) were prepared via immobilizing silane-functionalized ionic liquids (IL) onto the monodispersive silica nanoparticles, and the composite material was then applied in the immobilization of penicillin G acylase (PGA, EC 3.5.1.11), an important industrial enzyme for the production of semisynthetic antibiotics. This was a novel approach of immobilizing PGA proposed in our previous report, in which we had studied the effects of IL types on the performance of this novel support. Here, we focused on the effects of IL loading on the properties of the SILs and their performance in PGA immobilization. The effects of silica sizes and routes of preparing SILs (the solvent route and the sol–gel route) on IL loading were investigated. The results showed that (1) the IL loading could be tuned efficiently by changing the silica sizes. (2) As compared with the solvent route, the sol–gel route is more simple, time-saving, and ecofriendly in operation. What's more, it has a higher IL loading. Among the factors affecting the IL loading, the reaction time was the most feasible factor to control to tune the IL loading, as compared with the temperature and the dosage of ILs. (3) With the increase of IL loading, the surface ζ-potential of silicas changed from negative to positive, and the isoelectronic point (IEP) increased accordingly, which caused the decrease of the protein loading but the increase of apparent and specific activity. A reusability experiment showed that the sol–gel 1 sample maintained approximately 55% of the initial activity even after 10 consecutive operation cycles under the experimental conditions. This activity was 3.7 times higher than that of the sol–gel 2 sample.

Functionalised heterogeneous catalysts for sustainable biomass valorisation

“…39 Supported ionic liquids (SILs) offer several advantages for catalytic biomass conversions over the corresponding pristine ILs. 40,41,279,280 SILs not only combine the original properties of ILs and supports, but also endows new functional sites and robust stabilisation, due to synergistic IL-support interactions. It is also possible that deposition of ILs on a high specific surface area material can provide increased number of accessible active…”

“…281 Moreover, the particle size of the support as well as the synthesis routes of the SILs can also affect the catalytic activity. 279 Particularly, grafting of ILs, a widely used method, can considerably alter the activity of SILs in various ways. 282 The advantages of grafting compared to impregnation are confirmed by CO 2 diffusivity measurements.…”

“…Finally, the IL loading can also exert a significant role in tuning the surface properties of SILs to achieve better catalytic activity. 279 The loading of ILs can be adjusted by controlling the particle size of the support and the preparation method.…”

Preparation, characterization, and Ce(III) adsorption performance of poly(allylamine)/silica composite

“…(2014) [1][2][3][4][5][6][7][8][9][10][11][12][13][14] www.deswater.com doi: 10.1080/19443994.2014.944221 from further solvent extraction stages [5]. Ion exchange using polymeric resins and solvent extraction has become the most useful procedure for extraction and separation of REEs.…”

“…Noticeably, silica can effectively overcome the drawback of resin in mechanical strength [7,8]. Nevertheless, the adsorption capacity of pure silica is generally low because of the evident lack of adsorption sites on its surface.…”