Development of biofuel cell based on anode modified by glucose oxidase, Spirulina platensis-based lysate and multi-walled carbon nanotubes

Abstract

In this study, the GC/PEI/CNT/S.p./GOx bioanode was successfully designed using the chemical oxidized multi-walled carbon nanotubes (CNT) and Spirulina platensis-based lysates that facilitate the electron transfer and reduce the open circuit potential (OCP) drop along the electron transfer pathway. Composition, morphology and chemical modification efficiency of CNT was examined using scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and simultaneous thermal analysis (STA) coupled with mass spectrometric (MS) analysis of evolving gaseous species (TG/DTA–MS). The power density generated by GC/PEI/CNT/S.p./GOx bioelectrode was 21.8 times higher if S. platensis-based lysates were applied in bioanode design (than GC/PEI/CNT/GOx bioelectrode). The magnitude of maximal power density evaluated by linear sweep voltammetry (LSV) measurements was estimated to be 3.2 µW cm−2 at 213 mV voltage, whereas the bioelectrode act as a bioanode and bare glassy carbon as a cathode in a single-compartment biofuel cell design. Furthermore, the GC/PEI/CNT/S.p./GOx bioanode shows high long-term stability, while the magnitude of power density after seven days achieved approximately 89.6 % (2.87 µW cm−2) of its initial value. The initial OCP value of bioanode with S. platensis-based lysates was found to be -156 mV, which was reduced after the addition of 12.5 mM glucose. The equilibrated average value of OCP (-259 mV vs Ag/AgCl (3 M KCl)) indicates that glucose oxidase (GOx) immobilized on CNT functionalized with S. platensis-based lysates possess superior electron transfer and reduce the OCP drop along the electron transfer pathway.