Seven inducible promoters for Zymomonas mobilis

Zymomonas mobilis is an ethanologenic Alphaproteobacterium with many interesting characteristics for fundamental research and applied microbial engineering. Although genetic engineering has been established for Z. mobilis since the 1980s, a rich set of inducible transcriptional regulators is still unavailable. In this work, seven different chemically inducible promoters have been systematically tested for their functionality in Z. mobilis. In particular, for the first time, NahR-P_salTTC, VanR^AM-P_vanCC, CinR^AM-P_cin and LuxR-P_luxB have been characterized in Z. mobilis, alongside the commonly used regulator-promoter pairs TetR-P_tet and LacI-P_{lacT7A1_O3O4}, and the less commonly used XylS-P_m. All promoters investigated in this work are compatible with the Golden Gate modular cloning framework Zymo-Parts. Characterization was carried out with a shuttle vector backbone based on pZMO7, which has so far been rarely used for applications in Z. mobilis but is stable without selection and generates high and uniform levels of expression. From the experimental results presented, it can be concluded that VanR^AM-P_vanCC and CinR^AM-P_cin are particularly promising for broad use in the Z. mobilis community.