Phenazine enables the anaerobic respiration of Pseudomonas aeruginosa via electron transfer with a polarised graphite electrode

Pseudomonas aeruginosa PAO1 is widely distributed in fresh water, soil, and marine environments and can act as electrochemically active bacteria for bioconversion in bioelectrochemical systems. Phenazine, an active redox compound produced by PAO1, could be beneficial for its producers as an alternative respiratory pigment. Here, we demonstrated that phenazine promoted electron transfer of PAO1 to poised-potential electrodes, thus facilitating the anaerobic growth of P. aeruginosa PAO1. The growth and extracellular electron transfer of P. aeruginosa PAO1 were studied under four anaerobic conditions: with poised potential but without phenazine, with phenazine but without poised potential, with both phenazine and poised potential, and without phenazine and without poised potential in a phosphate-buffered saline medium bioreactor. The results showed that anaerobic conditions, without polarized electrode or without phenazine, did not support the colony formation of P. aeruginoa PAO1 on filters. Phenazine enhanced the electron transport between P. aeruginosa PAO1 and poised-potential electrode. These findings provided an insight into understanding the anaerobic respiration of P. aeruginosa PAO1 with poised-potential electrodes.