Yeast Surface Displaying Glucose Oxidase as Whole-Cell Biocatalyst: Construction, Characterization, and Its Electrochemical Glucose Sensing Application

Abstract

The display of glucose oxidase (GOx) on yeast cell surface using a-agglutinin as an anchor motif was successfully developed. Both the immunochemical analysis and enzymatic assay showed that active GOx was efficiently expressed and translocated on the cell surface. Compared with conventional GOx, the yeast cell surface that displayed GOx (GOx-yeast) demonstrated excellent enzyme properties, such as good stability within a wide pH range (pH 3.5-11.5), good thermostability (retaining over 94.8% enzyme activity at 52 °C and 84.2% enzyme activity at 56 °C), and high d-glucose specificity. In addition, direct electrochemistry was achieved at a GOx-yeast/multiwalled-carbon-nanotube modified electrode, suggesting that the host cell of yeast did not have any adverse effect on the electrocatalytic property of the recombinant GOx. Thus, a novel electrochemical glucose biosensor based on this GOx-yeast was developed. The as-prepared biosensor was linear with the concentration of d-glucose within the range of 0.1-14 mM and a low detection limit of 0.05 mM (signal-to-noise ratio of S/N = 3). Moreover, the as-prepared biosensor is stable, specific, reproducible, simple, and cost-effective, which can be applicable for real sample detection. The proposed strategy to construct robust GOx-yeast may be applied to explore other oxidase-displaying-system-based whole-cell biocatalysts, which can find broad potential application in biosensors, bioenergy, and industrial catalysis.

General incorporation of diverse components inside metal-organic framework thin films at room temperature

“…The dissociation or dissolution of functional components is avoided, allowing the incorporation of bio-components into MOFs without degrading their bio-functions. The enzymatic activity of GOx, which is very sensitive to glucose [54][55][56][57] , is reserved after encapsulation into HKUST-1 matrices (Fig. 4 and Supplementary Fig.…”

“…12a). The reduction peaks of pure HKUST-1 and glass carbon are generated from the reduction of oxygen [54][55][56] . However, the redox current of a GOx/HKUST-1 composite thin film in the same negative potential range of À 0.4 to À 1.0 V dramatically decreases upon the addition of glucose, exhibiting the same effect as that of pure GOx immobilized on a GCE (Supplementary Fig.…”

“…12b). The competitive reactions of oxygen and glucose oxidation through the direct electron transfer of GOx can reduce the oxygen reduction current and have been used for glucose sensing 55,56 . The decrement of the reduction current of the GOx/HKUST-1 electrode in the presence of glucose should be due to encapsulated GOx.…”

Conformation, Bioactivity and Electrochemical Performance of Glucose Oxidase Immobilized on Surface of Gold Nanoparticles

“…3A, the AuNPs-GOD/GCE (curve d) showed the typical FAD/FADH 2 redox peaks [44,45,[49][50][51]. The peak potential separation (DE p = E pa -E pc ) was about 20 mV, suggesting a rapid electron transfer [52][53][54]. The CVs of GOD/GCE (curve a), AuNPs-MHA-GOD/GCE (curve b) and AuNPs-MUA-GOD/ GCE (curve c) also showed the pair of redox peaks.…”

Electrochemical Glucose Biosensor Based on Glucose Oxidase Displayed on Yeast Surface

“…Therefore, it is necessary to develop an eukaryotic cell surface display system for biosensor design. The active GO x with improved pH and thermal stability had been successfully expressed in S. cerevisiae [12]. We hereby describe in detail bioelectrode construction using the yeast displayed GO x and carbon nanotubes.…”