Introduction

In synthetic biology it is of great importance to have well characterized genetic elements. For model organisms, these genetic elements are usually well characterized, however for non-model organisms, like M. extorquens, this toolkit is lacking^{1, 2}. The ability to regulate gene expression provides many options for genetic engineering, therefore, we decided to build a parts collection testing constitutive and inducible promoters. As a backbone, a oriV-traJ’ origin with Tc^R was used (pTE100, which was a gift from Dr. Schada Von Borzyskowski (Addgene plasmid # 59395))¹. The promoter strength was assessed using an mCherry testing cassette. We included the constitutively active promoters PmxaF, PfumC, PcoxB and Ptuf, which were previously characterized in M. extorquens by Schada Von Borzyskowski et al. (2015)¹. We included the IPTG inducible promoters P_L/O4/A1, which were previously published by Carrillo et al. (2019)². Additionally, we included an inducible promoter that was not yet characterized for M. extorquens specifically. In 2014, Kaczmarczyk et al. published a vanillate inducible promoter, P_V10 for expression in Sphingomonas³.