Optimizing glutaraldehyde modification in microbial consortium biofilm for enhanced ethanol detection

Abstract

Biosensors are analytical devices that combine biological components with physicochemical detectors to detect certain chemical substances. Modifying the biosensor surface with glutaraldehyde, which is a cross-linking agent with superior adhesive and binding properties for proteins and enzymes, can protect the ADH enzyme, thereby increasing the sensitivity and stability of the biosensor in ethanol detection. Screen-printed carbon electrode (SPCE) is used to attach a consortium of microbes producing the ADH enzyme modified with glutaraldehyde. Determining the technique for drop-casting the supporting material glutaraldehyde with a microbial consortium in making ethanol biosensor biofilms that provide the greatest response to the oxidation current. The drop-casting technique in preparing modified glutaraldehyde-microbial consortium biofilms which provides a higher oxidation current is by drop-casting the supporting material glutaraldehyde first and then drop-casting the microbial consortium in a 1:1 ratio with a low glutaraldehyde concentration. The performance of the glutaraldehyde modified-microbial consortium biofilm was assessed using the cyclic voltammetry method. The results indicated that the linear range, linearity, coefficient of determination, and sensitivity, were 0.1–6.0%, 0.9953, 0.9926, and 82.810 μA(%)−1. The LoD and LoQ theoretical values for the method obtained in the ethanol oxidation reaction were 0.039% and 0.118%, respectively. The biosensor had precise %RSD values of 0.194, 1.856, and 3.512% at high, medium, and low ethanol concentrations, respectively. The recovery percentage ranged from 95.5 to 102%. The biofilm demonstrated ethanol oxidation activity, which remained stable at 93% over ten measurements with %RSD of 2.743%.

Keywords

• Ethanol biosensor
• Glutaraldehyde
• S. cerevisiae
• Bacillus megatherium
• Microbes consortium