TY - JOUR T1 - Pantothenate auxotrophy in <em>Zymomonas mobilis</em> ZM4 is due to a lack of aspartate decarboxylase activity JF - bioRxiv DO - 10.1101/144709 SP - 144709 AU - J. R. Gliessman AU - T. A. Kremer AU - A. A. Sangani AU - S. E. Jones-Burrage AU - J. B. McKinlay Y1 - 2017/01/01 UR - http://biorxiv.org/content/early/2017/05/31/144709.abstract N2 - The bacterium Zymomonas mobilis naturally produces ethanol at near theoretical maximum yields, making it of interest for industrial ethanol production. Z. mobilis requires the vitamin pantothenate for growth. Here we characterized the genetic basis for the Z. mobilis pantothenate auxotrophy. We found that this auxotrophy is due to the absence of a single gene, panD, encoding aspartate-decarboxylase. Heterologous expression of Escherichia coli PanD in Z. mobilis or supplementation of the growth medium with the product of PanD activity, β-alanine, eliminated the need for exogenous pantothenate. We also determined that IlvC, an enzyme better known for branched-chain amino acid synthesis, is required for pantothenate synthesis in Z. mobilis, as it compensates for the absence of PanE, another pantothenate synthesis pathway enzyme. In addition to contributing to an understanding of the nutritional requirements of Z. mobilis, our results have led to the design of a more cost-effective growth medium. ER -