Sulfate reduction with electrons directly derived from electrodes in bioelectrochemical systems

In this paper, we reported microbially catalyzed sulfate reduction with polarized electrode (− 400 mV vs. Ag/AgCl) as the sole electron donor. In potentiostatic batch assays, sulfate was reduced to sulfide, at rates falling in the range of 6.70–12.16 equiv./l d. Cyclic voltammetry tests revealed that the sulfate-reducing biofilms could accept electrons from electrodes directly without via electron shuttles or hydrogen production. Scanning electron microscope revealed that the electrode was colonized by several ellipse-shaped and short rod-shaped microorganisms, which closely related to Desulfobulbus propionicus and Geobacter species.

► Microbially catalyzed sulfate reduction with electrode as sole electron donor was achieved.
► Direct electron transfer from electrode to microbes was proved.
► Dc propionicus and Geobacter species played the key role for electron transfer.