초록
<P><B>Abstract</B></P> <P>Electro-fermentation is gaining attention for its advantage in promoting product recovery and valorization of organic wastes. However, emission of by-product gases during acidogenic fermentation is one of the key reasons for reduced product recovery whereas high gas pressure in the acidogenic headspace could pose an inhibitory effect on the production of volatile fatty acids (VFAs). This study presents a novel electro-fermentation (EF) system for enhancing VFAs production by in situ reuse of anodic off-gases (mainly CO<SUB>2</SUB> and H<SUB>2</SUB>) in the cathode. A total VFAs production of 0.57 g-VFAs/g-VS was achieved through reuse of acidogenic off-gases in EF system, corresponding to 48.70% increase in comparison with the treatment without off-gases reuse. Consequently, the conversion efficiency of carbon to VFAs was improved significantly by 13.92%. Acidogenic metabolic pathway in the anode shifted to mixed -acid fermentation with the succession of dominant microbes from genus of <I>Escherichia</I> in the seeding inocula to <I>Bacteroides</I> and <I>Desulfovibrio</I> in the anode and cathode chambers, respectively. This would provide a way to enhance VFAs recovery from organic wastes, which also contributes to reduced carbon footprint and increased environmental sustainability.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A novel electro-fermentation system was designed. </LI> <LI> VFAs production was enhanced by in situ reuse of anodic off-gases in the cathode. </LI> <LI> The conversion efficiency of carbon to VFAs was improved. </LI> <LI> Acidogenic metabolic pathway in the anode shifted to mixed acids production. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>