Insight into the dehydrogenase catalyzed redox reactions and electron discharge pattern during fermentative hydrogen production

Dehydrogenase (DH) activity associated with bio-electrochemical behavior was analyzed for the first time to understand the redox reactions involved in fermentative hydrogen (H2) production process in concurrence with proton (H+) shuttling and electron (e−) discharge (ED) pattern. DH facilitates the availability of H+ through redox reactions to make H2. We have designed a comprehensive experimental study to evaluate the DH activity (H+ shuttling) and ED to understand the biochemical process with the function of pH (5, 6, 7 and 8) and metabolic microenvironment [anaerobic, anoxic and aerobic (control)]. DH activity was observed to be higher during anaerobic operation suggesting the higher availability of H+ and e− due to the inter-conversion of metabolites and the same was reflected in the voltammetry analysis. Higher H2 production under anaerobic operation corroborated well with these findings. The DH activity associated with H+ shuttling and ED was also correlated with the substrate degradation pattern.