Background A range of yeasts has been developed as attractive production systems for recombinant proteins. Some like Hansenula polymorpha [1] are already distinguished by an impressive track record as producers of valuable proteins that have already reached the market whereas other newly defined systems like Arxula adeninivorans [2] have yet to establish themselves but demonstrate a great potential for industrial applications. All yeast systems have special favorable characteristics, but also limitations and drawbacks – as is the case with all expression systems. As there is clearly no single system that is optimal for all possible proteins, it is advisable to assess several selected organisms in parallel for their capability to produce a particular protein in desired amounts and quality to avoid costly timeand resource-consuming failures. The availability of a vector that can be targeted to the various platform candidates would greatly facilitate such a comparison. As such a vector system (CoMedTM) has been designed that is built up in a modular way [3]. Certain combinations of elements result in vectors that can be addressed to a wide range of yeast hosts.