초록
<P><B>Abstract</B></P> <P>Electro-fermentation has been recently proposed as a new operational mode of bioprocess control using polarized electrodes. This paper aims to evaluate how polarized electrodes are affecting microbial metabolic fermentative pathways, with a special focus on how the bacterial populations are affected during hydrogen production by dark fermentation. Four different potentials were applied on the working electrode in batch electro-fermentation tests operated with mixed culture and using glucose as a substrate. Two different metabolic behaviours for H<SUB>2</SUB> production were observed in electro-fermentation. The first one led to a higher H<SUB>2</SUB> production compared to conventional fermentation with a strong selection of <I>Clostridium</I> sp. The second behaviour led to lower H<SUB>2</SUB> production along with ethanol, and strongly correlated with the selection of <I>Escherichia</I> and <I>Enterobacter</I> genera. However, the effect of the applied potential on population selection was mostly non-linear and no simple relationship was found between these two parameters. Overall, electro-fermentation process has shown its potential as a new type of control for mixed-culture bioprocesses with significant effects of polarized electrodes on glucose fermentation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Electro-fermentation increased hydrogen yields while decreasing lactate production. </LI> <LI> Well known hydrogen-producing bacteria were selected during electro-fermentation. </LI> <LI> Small amount of current was sufficient to trigger population selection. </LI> </UL> </P>