Increasing biohydrogen production with the use of a co-culture inside a microbial electrolysis cell

Biohydrogen (H-2) is considered to be a significant contributor to sustainable economy. However, due to current yields and production rates, large-scale technical implementation of biological H-2 production is still a long way off. In this study, two highly productive H-2 producers, Enterobacter aerogenes and Clostridium acetobutylicum, were synergistically combined in an artificial microbial consortium (co-culture) for H-2 production. Moreover, this co-culture was utilized in a bioelectrochemical system referred to as microbial electrolysis cell, where a small voltage (0.8 V) is applied to enforce H-2 production. The experiments were conducted in closed batch mode using cellobiose as carbon source. Each of the applied approaches (co-culture and applied voltage) led to an increase in H-2 evolution rate (HER), resulting in a maximum HER of 0.93 mmol L-1 h(-1) for the co-culture at an applied voltage of 0.8 V. With the further scale-up and optimization of the examined system parameters, sustainable H-2 production for large-scale applications might be feasible within the near future.