Multi‐Enzyme‐Modified Bioanode Utilising Starch as a Fuel

Abstract

A new multi-enzyme bioanode utilising starch, maltose, and glucose as fuels is demonstrated. The unique combination of αamylase, glucoamylase, mutarotase, and flavin-adenine dinucleotide-dependent glucose dehydrogenase enables the bioanode to utilise a polysaccharide, starch, as a fuel. Replacing αamylase and glucoamylase with β-amylase and maltase does not lead to effective starch degradation, possibly because of termination of the cleaving reaction by β-AMY at the branching point of the starch molecules. Furthermore, by using a reduced graphene oxide/multi-walled carbon nanotubes composite as the carbon support for enzyme immobilisation, the new bioanode demonstrates a high oxidation current density of 5.8 mA cm À 2 in neutral phosphate-buffered solution containing 0.8 % (w/v) starch. Finally, a bioanode containing the six enzymes, α-amylase, β-amylase, glucoamylase, maltase, mutarotase, and flavin adenine dependent glucose dehydrogenase, is fabricated. The fabricated bioanode is effective in degrading glucose, maltose, and starch. Thus, this study provides an important fundamental strategy for controlling the applicability of bioanodes by adjusting the loaded enzymes.

Surfactant-Free Formate/O2 Biofuel Cell with Electropolymerized Phenothiazine Derivative-Modified Enzymatic Bioanode

“…First, the effect of the cross-linking agent used for enzyme modification was examined. Figure S1 shows the cyclic voltammograms of electrodes prepared using GA and PEGDGE as enzyme cross-linkers and polyMB as the electrocatalyst. PolyMB was selected based on the previous report .…”

“…Enzymatic biofuel cells generate electricity through the enzyme-catalyzed oxidation of organic materials − such as saccharides (glucose, − fructose, , maltose, and starch − ), alcohols (methanol − and ethanol − ), and formic acid , and feature milder operation conditions (room temperature, neutral pH, and ambient pressure) compared to typical inorganic-catalyst fuel cells. The substrate specificity of enzymes obviates the need for anode–cathode separation and thus facilitates cell miniaturization and applications in wearable − and implantable − devices.…”

“…Carbon materials are widely used in enzymatic biofuel cells to increase the enzyme modification density. ,− In particular, carbon nanotubes (CNTs) enjoy high popularity due to their high specific surface area and electrical conductivity. ,,,− The high propensity of CNTs for agglomeration is typically mitigated through the addition of surfactants to disperse CNT for drop-coat process. ,,,, However, they inevitably dissolve from the CNT electrode into the electrolyte and thus hydrophilize an opposite gas-diffusion biocathode to cause electrolyte leakage and/or reduce fuel-cell performance due to electrolyte flooding and the loss of oxygen supply to the biocathode . Therefore, the preparation of surfactant-free bioanodes is essential for the realization of high-performance formate/O 2 biofuel cells.…”

Surface Properties of Alkyldi(oxyethylene) β-D-Maltoside

“…D-maltose ( 1 ) is a disaccharide, a drug accessory, a multi-enzyme-modified bioanode, a nanopore tweezer, and a flexible artificial synapsis commonly used for the table. They should have an excellent common sense of the required characteristics, edibility, drug dispersibility/absorptivity, and help to reasonably explain oxidation, conformational dynamics/intelligent design/substrate recognition, mechanical endurability, and even thermo-acoustic property .…”

“…10 Furthermore, characteristic 1,2-cis or 1,2-trans alkyl glycosides (AGs) should probably have an excellent structure−physicochemical properties−functionality relationship, biocompatibility, and environmental sustainability owing mainly to their controlled structure with anomeric purity and no/low irritation/toxicity since they are amphiphilic molecules having hydrophobic alkyl chains, hydrophilic glycosyl groups, and even other useful structural segments. 1,3,11 D-maltose (1) is a disaccharide, a drug accessory, a multienzyme-modified bioanode, 12 a nanopore tweezer, 13 and a flexible artificial synapsis 14 commonly used for the table. They should have an excellent common sense of the required characteristics, edibility, drug dispersibility/absorptivity, and help to reasonably explain oxidation, conformational dynamics/intelligent design/substrate recognition, mechanical endurability, and even thermo-acoustic property.…”