Combining the genes described above with the Biosafety-Strain K-12 ∆alr ∆dadX results in a powerful device, allowing us to control the bacterial cell division. The control of the bacterial growth is possible either active or passive. Active by inducing the tetO operator with tetracycline and passive by the induction of L-rhamnose. The passive control makes it possible to control the bacterial cell division in a defined closed environment, like the MFC, by continuously adding L-rhamnose to the medium. As shown in Figure 7 below, this leads to an expression of the essential alanine racemase (alr) and the TetR repressor, so that the expression of the RNase Ba is repressed.