The Reason for Bacterial Evolution of Hydrogen by Fermentation and the Problems to be Solved for Utilization on Energy Production

Abstract

Hydrogen evolution by fermentation is very general metabolism for bacteria. Almost 25% of generalisted in the Bergey’s Manual of Determinative Bacteriology, 8^th edition, were recognized to evolve hydrogen, no matter what the amount of evolution. The reason is mainly to re-oxidize NADH to NAD⁺ to get more energy for their growth and living like follows; NADH+H⁺→ NAD⁺+H₂. For the case of Clostridium butyricum, the evolution was clearly explained from the point of chemical thermodynamics. The metabolism is regulated by the redox potential of H₂ at the cultural pH. Maximum values on hydrogen production properties were estimated from the theoretical point of view.