Electroactive mixed culture derived biofilms in microbial bioelectrochemical systems: The role of pH on biofilm formation, performance and composition

► The pH influences the formation and operation of electroactive microbial biofilms and their respective electron transfer thermodynamics. ► The biofilms (grown from municipal wastewater) can grow and adapt dynamically within a pH-window of pH 6-9. ► The microbial community dynamics can be followed and analysed using flow-cytometry and multivariate statistics. ► High performance biofilms are dominated by Geobacter sulfurreducens and low performance biofilms are more diverse.