Fluorescent probe based subcellular distribution of Cu(II) ions in living electrotrophs isolated from Cu(II)-reduced biocathodes of microbial fuel cells.

•Electrotrophs were isolated from Cu(II)-reduced biocathodes of microbial fuel cells.•Cu(II) removal rates of 2.90–3.64mg/Lh were achieved by these electrotrophs.•Fluorescent probe was used to successfully track Cu(II) ions in electrotrophs.•Cathodic electrons directed more Cu(II) ions for quicker entrance into cytoplasm.