Expansion kit for bioreactors used for performing microbial bio-electrosynthesis

An expansion kit for reversible introduction into a bioreactor for dividing the bioreactor into two separate reaction chambers and for performing microbial bio-electrosynthesis, wherein the expansion kit comprises a reaction chamber which is open at a top and which has a window in a sidewall, said window having a membrane disposed therein, characterized in that the expansion kit is formed such that, when the expansion kit has been introduced into the bioreactor:

• the reaction chamber of the expansion kit and a reaction chamber of the bioreactor are adjacent to each other on opposite sides of the sidewall and are connected to each other by the membrane disposed in the window of the sidewall, the expansion kit having a reactor lid that covers the open portions of both reaction chambers, the sidewall being coupled to and extending from the reactor lid such that the sidewall is substantially perpendicular to the reactor lid, the reactor lid having at least two through-openings into which electrodes are introduced in such a way that each of the electrodes projects into a separate one of the reaction chambers separated by the membrane and each of the electrodes functions as an anode or cathode.