The overlooked promotion of electricity generation by electrochemically active bacteria using chitosan.

The modification of electrodes with nanomaterials improves the adhesion of electrochemically active bacteria (EAB) and their generation of electricity. Although chitosan (CTS) is the most commonly used nanomaterial dispersant, its effects on EAB remain unclear. This study systematically investigates the effects of electrodeposited CTS on electricity production by EAB and elucidates the underlying biological mechanisms. The results demonstrate that EAB generates 14.19 times more electricity with a modified carbon cloth electrode containing electrodeposited CTS compared with an unmodified electrode. This enhancement of electricity production is primarily owing to slight improvements in conductivity and obvious increases in biomass. The relationship between the CTS electrodeposition time and enhancement of electricity exhibits an inverted U-shape, with an optimal time of 10 min. When the electrodeposition time is under 10 min, the content of amino groups is insufficient, which fails to promote the adhesion of EAB. In contrast, prolonged electrodeposition transforms amino groups into pyridinic nitrogen, which weakens the adhesion of EAB. Future studies on electrode modification for use by EAB should pay more attention to the addition of CTS, and distinguish the contributions of CTS and nanomaterials to the enhancement of electricity.