This work describes the first step towards combination of the bioreactor with a starch-degrading microbial consortium and hydrogenase electrode (HE) in one unit for electricity generation. For this purpose, the bioreactor for microbial fermentation was designed with a set of electrodes (pH-sensor, Ag|AgCl reference electrode. Pt-electrode, and HE) inside the bioreactor. Potentials of all electrodes and H-2 accumulation were monitored in the system under the precise pH control. Results obtained with the hydrogen-producing microbial consortium indicated that HE generates the potential equal to the H-2|2H(+) equilibrium potential. Furthermore. HE was able to catalyze the current generation (200 mu A) by consuming H-2 gas produced in the microbial consortium from starch. After 220 h of operation. HE retained at least 81% of the initial activity. Calculations of carbon balance indicated that fermentation products were similar in microbial cells without HE and with HE generating the current due to H2 consumption. (C) 2011 Elsevier Inc. All rights reserved.