# Mini-Review: Recent Technologies of Electrode and System in the Enzymatic Biofuel Cell (EBFC)
## 3 Current Development on the Bioanode and Biocathode in EBFC
In addition, this material creates supercapacitor features that are for charge storage. The results show that the performance of EBFC was maintained at 80% when used as a 50 charge/discharge pulse. [PERSON] et al. [71] also developed an enzymatic biosupercapacitor using gold nanoparticle-based paper and nanostructured polypyrrole/nanocellulose as electrode materials with specific characteristics capacitance of 1.8 F/cm\({}^{2}\). The supercapac gives one order magnitude of the current and power densities compared in the steady-state mode. A study by [PERSON] et al. [44] modified the poly binder (vinylidene difluoride) and polytetrafluoroethylene (PTFE) on the MgO-templated carbon at the anode and cathode of the EBFC, respectively. The enzyme used will be supported by MgO/porous carbon. PTFE will control the hydrophobicity of the cathode so that the mass transport of oxygen gas becomes easy. Gold (Au) electrode is commonly used in the EBFC cathode for oxygen reduction reactions (ORR). [PERSON] et al. [20] produced self-powered sensors using EBFC to detect atrazine. To achieve use of the EBFC as a sensor, the authors used aptamers (Apt) supported on the Au electrode on the cathode section. ATZ was present at the cathode chamber and then bound at the Apt/Au electrode. The Apt/Au electrode has high sensitivity because it can detect ATZ as low as 7.5 mM due to the Au electrode helping to increase the electron transferability. Although a Pt metal catalyst showed good catalysis in ORR, [PERSON] et al. [72] developed an iron and cobalt co-doped ordered mesoporous porphyrinic carbon (FeCo-OMPC) bioachtofore for cheaper ORR and achieved long-term stability. ORR activity increased with cobalt metal in the bioachtofore with a limited power density of 21.3 \(\upmu\)W/cm\({}^{2}\) compared to without cobalt metal (9.6 \(\upmu\)W/cm\({}^{2}\)). [PERSON] et al. [73] used the combination of gold nanoparticle-reduced graphene oxide and a poly neutral red polymer composite electrode to interact with both enzymes at the bioanode and bioachtoode. Combining the gold nanoparticle-reduced graphene oxide increases the stability, selectivity, and high chemical structure by interacting with the poly neutral red polymer that enhances the electron transfer and thus operates the EBFC at 0.2 V and power of 3.6 \(\upmu\)W/cm\({}^{2}\). [PERSON] et al. [74] focused on cathode studies to improve EBFC performance by using tris-(2-aminoethyl) amine (TREN) as a linker for the connection between Au nanoparticles and the surface of CNT fibers. TREN is used to reduce electron transfer resistance because TREN is a short molecule compared to other linkers/binders. These layer-by-layer Au nanoparticles produce power as high as 1.2 mW/cm\({}^{2}\). The arrangement of the enzyme on the electrode surface plays a vital role so that the utilization of the enzyme can be maximized and provide excellent contact between the enzyme and the electrode surface. The work of [PERSON] et al. [75] resulted in cascade enzyme arrangement at the anode of the EBFC. In this study, various enzymes were used, namely mutarotase, invertase, fructose dehydrogenase, and flavine adenine dinucleotide (FAD)-dependent glucose dehydrogenase in addition to using single or mixed substrates such as glucose, fructose, and sucrose. The comparison of other studies in this study shows that the resulting bioanode can produce a current as high as 2230 \(\upmu\)A/cm\({}^{2}\) and maintain power generation for eight days before falling by 38%. Enzyme arrangement using nanoparticles that have a high surface area to volume ratio for enzyme loading [16] leads to a reduction in the distance of electron transport [75] and thus enhances the performance and stability of the EBFC [33]. EBFC can be applied as self-powered sensors to detect environmental pollutants. Pollutants such as atrazine are very harmful to humans and the environment, even at low ppb levels.