NOVELTY - An oxidation-reduction fuel cell (500) comprises membrane electrode assembly (A) and membrane electrode assembly (B). The membrane electrode assembly (A) includes nitrogen monoxide-containing sample injection port, anode, fuel cell (100) and cathode conjugated to the fuel cell (100). The membrane electrode assembly (B) includes nitrogen monoxide-containing sample discharge port, anode, fuel cell (200) and cathode. The nitrogen monoxide-containing sample contains filler, iron(III) ethylenediamine tetraacetic acid, iron(III) nitrilotriacetic acid and iron(III) methyliminediacetic acid.    USE - Oxidation-reduction fuel cell is used for separation of nitrogen oxide from nitrogen oxide-containing sample for preparation of nitric acid for manufacture of ethanol (all claimed).    ADVANTAGE - The oxidation-reduction fuel cell efficiently separates nitrogen oxide from nitrogen oxide-containing sample, by a simple process. The ethanol is efficiently manufactured by the separated nitrogen oxide.    DETAILED DESCRIPTION - An oxidation-reduction fuel cell comprises membrane electrode assembly (A) and membrane electrode assembly (B). The membrane electrode assembly (A) includes nitrogen monoxide-containing sample injection port, anode, fuel cell (100) and cathode conjugated to the fuel cell (100). The membrane electrode assembly (B) includes nitrogen monoxide-containing sample discharge port, anode, fuel cell (200) and cathode conjugated to the fuel cell (200). The nitrogen monoxide-containing sample contains filler, iron(III) ethylenediamine tetraacetic acid, iron(III) nitrilotriacetic acid and iron(III) methyliminediacetic acid. INDEPENDENT CLAIMS are included for the following:    (1) separation of nitrogen oxide from nitrogen oxide-containing sample; and    (2) manufacture of ethanol, which involves culturing microorganism in culture medium, adding enzyme, and saccharifying lignocellulosic biomass by nitric acid prepared by the separated nitrogen oxide.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the oxidation-reduction fuel cell.    Fuel cells (100,200)    Fuel supply portion (300)    Oxidizing agent inlet port (400)    Oxidation-reduction fuel cell (500)