Tailoring Galactose Oxidase for Self‐Powered Benzyl Alcohol Sensing

Abstract

AbstractBenzyl alcohol (BnOH) is a widely‐used preservative in a variety of cosmetics, but the excess addition (≥1.0 %) may cause strong symptoms such as nausea, gastrointestinal irritation, convulsion, even death, making it crucial to monitor and control the addition quantity. Herein, we have developed a test‐strip‐like BnOH detection method via tailoring a galactose oxidase (GOase) towards BnOH oxidation and preparing a self‐powered electrochromic strip for BnOH concentration visualization. A double‐substituted GOase variant (Y329S/R330F), on the basis of the reported GOase M1, has been obtained by semi‐rational design with a 24.6‐fold improved activity towards BnOH compared to GOase M1. The GOase Y329S/R330F electrode has a response to BnOH with a linear range of 0.04 to 3.25 mM (R2=0.9985), a sensitivity of 122.78 μA mM−1 cm−2, and a detection limit of 0.03 mM (S/N=3). Coupling an electrochromic Prussian blue (PB) cathode helps the successful sensing visualization without any further power supply. The present sensing is more convenient and user‐friendly than the generally used gas chromatography (GC) and high performance liquid chromatography (HPLC), and brings a more accessible solution to the field of quality controlling.