Abstract: A glutamate oxidase that requires no protease treatment is produced. A glutamate oxidase mutant having a deletion of a predetermined amino acid sequence is also disclosed.

Abstract: A fuel cell system of an embodiment includes a fuel cell stack including a fuel electrode layer, an oxidizer electrode layer, and a cooling layer, a fuel-gas flow path configured to allow the fuel gas from the fuel electrode layer to pass therethrough, an oxygen-containing-gas flow path configured to allow the oxygen-containing gas from the oxidizer electrode layer to pass therethrough, a cooling-water flow path, a first bypass pipe configured to guide water in the fuel-gas flow path to the cooling-water flow path, a second bypass pipe configured to guide water in the oxygen-containing-gas flow path to the cooling-water flow path, and a suction pump provided in the cooling-water flow path on the downstream side of a connecting portion between the cooling-water flow path and the first bypass pipe and a connecting portion between the cooling-water flow path and the second bypass pipe.

Abstract: According to one embodiment, a fuel cell system supplies high-pressure oxygen to a fuel cell by a compressor unit in which a compressor and a turbine are interlocked. An oxygen-containing gas flowing out from an oxygen-containing gas flow path flows into a cooling water tank and then is discharged. Cooling water is supplied from the cooling water tank to a cooling water flow path in the fuel cell.

Abstract: A fuel processing system is disclosed which supplies a hydrogen-rich gas to a fuel cell main unit. When supply of raw fuel is stopped, the fuel processing system executes a purge treatment to cause steam to flow as a purge gas in a forward direction and to cause air to flow in the opposite direction. Residual gas in the device is purged by this purge treatment.