High-level succinic acid production by overexpressing a magnesium transporter in Mannheimia succiniciproducens

Abstract

<jats:p> Succinic acid (SA), a dicarboxylic acid of industrial importance, can be efficiently produced by metabolically engineered <jats:italic>Mannheimia succiniciproducens</jats:italic> . Although the importance of magnesium (Mg <jats:sup>2+</jats:sup> ) ion on SA production has been evident from our previous studies, the role of Mg <jats:sup>2+</jats:sup> ion remains largely unexplored. In this study, we investigated the impact of Mg <jats:sup>2+</jats:sup> ion on SA production and developed a hyper-SA producing strain of <jats:italic>M. succiniciproducens</jats:italic> by reconstructing the Mg <jats:sup>2+</jats:sup> ion transport system. To achieve this, optimal alkaline neutralizer comprising Mg <jats:sup>2+</jats:sup> ion was developed and the physiological effect of Mg <jats:sup>2+</jats:sup> ion was analyzed. Subsequently, the Mg <jats:sup>2+</jats:sup> ion transport system was reconstructed by introducing an efficient Mg <jats:sup>2+</jats:sup> ion transporter from <jats:italic>Salmonella enterica</jats:italic> . A high-inoculum fed-batch fermentation of the final engineered strain produced 152.23 ± 0.99 g/L of SA, with a maximum productivity of 39.64 ± 0.69 g/L/h. These findings highlight the importance of Mg <jats:sup>2+</jats:sup> ions and transportation system optimization in succinic acid production by <jats:italic>M. succiniciproducens</jats:italic> . </jats:p>