Our aim was to transport Vitamin B₁₂, a substance which has no known cellular exporter in nature, through the inner membrane out of the cytoplasm. Our different B₁₂ Synporter proteins consist of TorA signal peptide for the Twin Arginine Translocation (Tat) system mediated export that is linked to a B₁₂-binding domain. This construct was produced, together with B₁₂, by the B₁₂ autotrophic R. planticola and S. blattae.

We could show that the Synporter proteins were translocated into the periplasm, prooving that the Tat mediated translocation was successful. Moreover, most important, we could also prove a significantly increased overall B₁₂ production in the cells expressing the Synporter protein, compared to the cells containing an empty plasmid. This significantly increased B₁₂ production, caused by a leak of B₁₂ out of the cell, proves that our Synporter is functional. This is the first time reported that a high-molecular compound as B₁₂ was translocated through a cellular membrane without a native exporter, which makes our Synporter so innovative.

Thereby, Vitamin B₁₂ can also be regarded as a prime example which is what we want to state with our work. In principle, a Synporter should work with basically any desired chemical compound, if a protein counterpart exists which can be used as Synporter binding domain. This concept can be applied for the production of all natural chemicals which are synthesized, but not exported due to the lack of a native cellular exporter. Furthermore, it can also be applied for the production of artificial molecules which can be produced by synthetic metabolic engineering in a cell. Using our Synporter approach, no cell lysis is required any more for the industrial production, which makes the production process significantly easier and cheaper.