Improvement of dark fermentation of biohydrogen production by release of acetic acid inhibition

Biological processes are an environmentally friendly technology for producing hydrogen from renewable resources. However, anaerobic fermentation is limited by high end products concentration and low pH value under unaffected conditions. To enhance hydrogen production by fermentative hydrogen producing bacterial strain B49 (AF481148 in EMBL), we have recently employed an electrodialytic cell to release critical acetic acid inhibition. Electrodialysis with bipolar membrane was utilized to remove acetic acid from original effluent of fermentation reactor, while another liquid end product - ethanol and residual glucose were recovered, and return to previous process. We report here that by optimizing the reactor configurations and operation conditions, the hydrogen yield increased to 2.4 mol H2/mol glucose with an average of pH of 4.5. The modified process moderated the critical pH and increased substrate utilizing rate.