Upgrade kit for bioreactors for carrying out the microbial Bioelektrosynthese

In order to provide an upgrade kit (100) for bioreactors (20) that allows an extension of bioreactors (20) according to the prior art, so that their use for microbial Bioelektrosynthese is possible, it is proposed that the upgrade set (100) open on one side reaction chamber (21) which in a side wall (22) has a window (23) which is provided with a membrane (24).