An engineering Escherichia coli mutant with high succinic acid production in the defined medium obtained by the atmospheric and room temperature plasma

• E. coli LL016 can grow in the defined medium obtained by ARTP.
• E. coli LL016 showed a high succinic acid productivity in the defined medium.
• High PTS activity in LL016 indicates an increase in glucose transport capacity.
• The high concentration of ATP was supplied by active PCK in LL016.
• The active PCK further improved cell growth and succinic acid production in LL016.

Escherichia coli BA002, the ldhA and pflB deletion strain, cannot utilize glucose in nutrient-rich or minimal media anaerobically. Co-expression of heterologous pyruvate carboxylase and nicotinic acid phosphoribosyltransferase in BA002 resulted in a significant increase in cell mass and succinic acid production. Nevertheless, the resultant strain, BA016, still could not grow in a defined medium without tryptone and yeast extract. To solve the problem, a novel atmospheric and room temperature plasma mutation method was employed to generate mutants which can grow in the defined medium. A mutant designated as LL016 was observed to be the best strain that regained the capacity of cell growth and glucose utilization in a defined medium anaerobically. After 120 h of fermentation in the defined medium, 35.0 g/L of glucose was consumed to generate 25.2 g/L of succinic acid. Furthermore, with the highest glucose consumption rate in the dual-phase fermentation, the yield of succinic acid in LL016 reached 0.87 g/g, which was higher than that observed in other strains. From an industrial standpoint, the defined medium is much cheaper than LB medium, which shows a great potential usage for the economical production of succinic acid by LL016.