Use of Cytochrome P450 Enzyme Isolated From Bacillus Stratosphericus sp. as Recognition Element in Designing Schottky-Based ISFET Biosensor for Hydrocarbon Detection

Cytochrome P450 enzyme isolated from an extremophile Bacillus Stratosphericus sp. was used as the recognition element for an ion-sensitive field effect transistor (ISFET)-based biosensor. The fabricated ISFET is Schottky-based and has silicon dioxide as a sensing layer. The cytochrome P450 component in its present purified form (pH-7.2) in 5% agarose was laid over the SiO 2 gate to examine its capability of generating electronic response in the presence of n-hexadecane and reduced nicotinamide adenine dinucleotide phosphate. The partially purified preparation was obtained from the lysozyme treated spheroplast via ion exchange chromatography followed by the gel filtration chromatography. The variation of potential difference between the gate and the source with respect to pH for the bare ISFET and the variation of gate and source potential difference with respect to the concentration of the measurand at constant current have been recorded for analyses. The observed correlation showed good repeatability of the sensor output suggesting a potential functional sensing device for hydrocarbon detection. The sensitivity parameters for the device have been determined to be 50.65 mV/pH and 54.34 mV/molar for the bare ISFET and enzyme field-effect transistor, respectively.