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Bio-Hydrogen: Electrical Fan Powered by our Engineered E. coli

Fuel Cell

In the fuel cell the hydrogen produced by a bacterial culture reacts with oxygen from air producing electricity and water.

Operation of a PEM fuel cell. (Taken from:

Diagram: How a PEM fuel cell works.  1. Hydrogen fuel is channeled through field flow plates to the anode on one side of the fuel cell, 
    while oxygen from the air is channeled to the cathode on the other side of the cell.  2. At the anode, a platinum catalyst causes the hydrogen to 
    split into positive hydrogen ions (protons) and negatively charged electrons.  3. The Polymer Electrolyte Membrane (PEM) allows only the positively 
    charged ions to pass through it to the cathode.  The negatively charged electrons must travel along an external circuit to the cathode, creating an electrical current.  
    4. At the cathode, the electrons and positively charged hydrogen ions combine with oxygen to form water, which flows out of the cell.

Production of Bio-Hydrogen

An overnight culture (50 mL) of E. coli BW25113 hyaB hybC hycA fdoG/pCA24N-fhlA (1) in complex-formate (100 mM) medium was used to inoculate 175 mL of fresh complex-formate (100 mM) medium; the culture was sparged with nitrogen, to remove oxygen, and incubated under anaerobic condition for six hours at 37oC.


A fan with an electric load of 20 mW was connected to the output of the fuel cell. Catalog # 7306 (Hydrogen & Fuel Cell,Claremont, CA).


  1. "Metabolic Engineering to Enhance Bacterial Hydrogen Production," T. Maeda, V. Sanchez-Torres, and T. K. Wood, Microb. Biotechnol., 1: 30-39 (2008).

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