Systemic Analysis of the Spatiotemporal Changes in Multi-Species Electroactive Biofilms to Clarify the Gradual Decline of Current Generation in Microbial Anodes

The decrease in the electrochemical activity of multi-species microbial anodes in bioelectrochemical systems is the main bottleneck to overcome for bringing these technologies one-step closer to the industrialization stage. In this study, microsized stainless steel electrodes were implemented to investigate the distinctive electrochemical behavior of salt marsh electroactive biofilms (EABs). Four main temporal stages of biocolonization and electrochemical activity were thoroughly described. Maximum biofilm growth rate, high viability and high extracellular protein matrix content favored the increasing electrochemical activity of the EAB up to its maximum current peak. Then, when gradual fall in current became irreversible, biofilm growth rate decreased together with dead cells accumulation and an increase for extracellular polysaccharides. In addition, analyses of microbial populations showed a shift from Marinobacterium spp. to Desulfuromonas spp. These findings suggest a chemical and microbial temporal evolution of the EAB, which can be directly correlated to the electrochemical performance of the bioanode.

Automated summary

This study investigated the electrochemical behavior of salt marsh electroactive biofilms using microsized stainless steel electrodes. The research described four temporal stages of biocolonization and electrochemical activity, and found that the growth rate, viability, and extracellular protein matrix content influenced the electrochemical activity of the biofilm. The study also observed a shift in microbial populations from Marinobacterium spp. to Desulfuromonas spp., which correlated to the electrochemical performance of the bioanode.