A cathode can include: an electrode substrate; a porphyrin precursor attached to the substrate; and an enzyme coupled to the electrode substrate to be associated with the porphyrin precursor, the enzyme reduces oxygen. The cathode can include a conductive material associated with the porphyrin precursor and/or the enzyme. The cathode can include 1-pyrenebutanoic acid, succinimidyl ester (PBSE) associated with the porphyrin precursor and/or the enzyme and/or the conductive material. The cathode can include 2,5-dimethyl-1-phenyl-1H-pyrrole-3-carbaldehyde (DMY-Carb) associated with the 1-pyrenebutanoic acid, succinimidyl ester (PBSE) and/or the porphyrin precursor and/or the enzyme and/or the conductive material. The porphyrin precursor is attached to the substrate through covalent coupling. In some aspects, substrate is linked to the porphyrin precursor, the porphyrin precursor is linked to the conductive material, the conductive material is linked to the PBSE, the PBSE is linked to the DMY-carb, and the DMY-carb is linked to the enzyme.

Disclosed is a lignin that is soluble in a medium having a pH greater than or equal to 4, a solution containing same, a method for producing same, and uses thereof, in particular for preparing lignin fibers and carbon fibers. Soluble lignin may be obtained by enzymatic modification.

A cathode can include: an electrode substrate; a porphyrin precursor attached to the substrate; and an enzyme coupled to the electrode substrate to be associated with the porphyrin precursor, the enzyme reduces oxygen. The cathode can include a conductive material associated with the porphyrin precursor and/or the enzyme. The cathode can include 1-pyrenebutanoic acid, succinimidyl ester (PBSE) associated with the porphyrin precursor and/or the enzyme and/or the conductive material. The cathode can include 2,5-dimethyl-1-phenyl-1H-pyrrole-3-carbaldehyde (DMY-Carb) associated with the 1-pyrenebutanoic acid, succinimidyl ester (PBSE) and/or the porphyrin precursor and/or the enzyme and/or the conductive material. The porphyrin precursor is attached to the substrate through covalent coupling. In some aspects, substrate is linked to the porphyrin precursor, the porphyrin precursor is linked to the conductive material, the conductive material is linked to the PBSE, the PBSE is linked to the DMY-carb, and the DMY-carb is linked to the enzyme.

An anode can include: an electrode substrate; a first region of the substrate having a catalyst composition located thereon, wherein the catalyst composition includes an inorganic or metallic catalyst; and a second region of the substrate having an enzyme composition located thereon, wherein the combination of the catalyst composition and enzyme composition converts a fuel reagent to carbon dioxide at neutral pH. The first region and second region can be separate regions. The catalyst of the catalyst composition can include gold nanoparticles. The catalyst can include an inorganic or metallic catalyst selected from vanadium oxide, titanium (III) chloride, Pd(OAc).sub.2, MnO, zeolite, alumina, graphitic carbon, palladium, platinum, gold, ruthenium, rhodium, iridium, or combinations thereof. The catalyst can be nanoparticle, nanorod, nanodot, or combination thereof. The catalyst can have sizes that range from about 10 to 20 nm.

The present invention relates to a novel Bacillus pumilus bilirubin oxidase, to the method for preparing same and also to the use thereof in particular for assaying bilirubin and for using enzymatic biofuel cells.

Disclosed are methods and apparatuses utilizing an O.sub.2-insensitive FDH2 from the sulfate-reducing bacterium (SRB) Desulfovibrio vulgaris Hildenborough (DvH). The O.sub.2-insensitive FDH2 may be applied to a biofuel cell for generating electricity and generating hydrogen peroxide. The biofuel cell can also be applied to wearable or implantable devices as a power source. The O.sub.2-insensitive FDH2 can also be used in other applications not applying a fuel cell, such as hydrogen peroxide generation, a formate testing kit, or carbon capture applications.