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. First, we could show that the Synporter proteins were translocated into the periplasm. Moreover, most important, we could also prove the enrichment of B₁₂ in the periplasm, which proofs 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 chemical (that can form a non-covalent bond to a protein), which is desired to be exported out of a cell.

This concept can be applied for the production of all natural chemicals which are synthesized, but not exported due to the lack of a 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.