Ferredoxin-dependent glutamate synthase (Fd-GltS) is reported as an enzymatic bioelectrocatalyst for the first time. By configuring mediated electrochemical interfaces with mediators of different redox potentials, we realize bioelectrosynthesis or bioelectrooxidation of glutamate with recombinant Fd-GltS from cyanobacteria. Particularly, bioelectrocatalytic oxidation of glutamate by Fd-GltS is demonstrated to be oxygen independent. This study reinforces a new catalytic option for developing enzymatic bioelectronic devices for powering, sensing or synthesis.