Systems and processes for producing hydrogen using bacteria are described. One detailed process for producing hydrogen uses a system for producing hydrogen as described herein, the system including a reactor. Anodophilic bacteria are disposed within the interior of the reactor and an organic material oxidizable by an oxidizing activity of the anodophilic bacteria is introduced and incubated under oxidizing reactions conditions such that electrons are produced and transferred to the anode. A power source is activated to increase a potential between the anode and the cathode, such that electrons and protons combine to produce hydrogen gas. In one system for producing hydrogen is provided which includes a reaction chamber having a wall defining an interior of the reactor and an exterior of the reaction chamber. An anode is provided which is at least partially contained within the interior of the reaction chamber and a cathode is also provided which is at least partially contained within the interior of the reaction chamber. The cathode is spaced apart at a distance in the range between 0.1-100 centimeters, inclusive, from the anode. A conductive conduit for electrons is provided which is in electrical communication with the anode and the cathode and a power source for enhancing an electrical potential between the anode and cathode is included which is in electrical communication at least with the cathode. A first channel defining a passage from the exterior of the reaction chamber to the interior of the reaction chamber is also included.