Adaptive laboratory evolution of Corynebacterium glutamicum towards higher growth rates on glucose minimal medium

作者：Pfeifer Eugen; Gaetgens Cornelia; Polen Tino; Frunzke Julia

来源：Scientific Reports, 2017, 7(1): 16780.

DOI：10.1038/s41598-017-17014-9

<jats:title>Abstract</jats:title><jats:p>In this work, we performed a comparative adaptive laboratory evolution experiment of the important biotechnological platform strain <jats:italic>Corynebacterium glutamicum</jats:italic> ATCC 13032 and its prophage-free variant MB001 towards improved growth rates on glucose minimal medium. Both strains displayed a comparable adaptation behavior and no significant differences in genomic rearrangements and mutation frequencies. Remarkably, a significant fitness leap by about 20% was observed for both strains already after 100 generations. Isolated top clones (UBw and UBm) showed an about 26% increased growth rate on glucose minimal medium. Genome sequencing of evolved clones and populations resulted in the identification of key mutations in <jats:italic>pyk</jats:italic> (pyruvate kinase), <jats:italic>fruK</jats:italic> (1-phosphofructokinase) and <jats:italic>corA</jats:italic> encoding a Mg<jats:sup>2+</jats:sup> importer. The reintegration of selected <jats:italic>pyk</jats:italic> and <jats:italic>fruK</jats:italic> mutations resulted in an increased glucose consumption rate and <jats:italic>ptsG</jats:italic> expression causative for the accelerated growth on glucose minimal medium, whereas <jats:italic>corA</jats:italic> mutations improved growth under Mg<jats:sup>2+</jats:sup> limiting conditions. Overall, this study resulted in the identification of causative key mutations improving the growth of <jats:italic>C. glutamicum</jats:italic> on glucose. These identified mutational hot spots as well as the two evolved top strains, UBw and UBm, represent promising targets for future metabolic engineering approaches.</jats:p>

• 出版日期2017-12-1