Production of Cadaverine in Recombinant Corynebacterium glutamicum Overexpressing Lysine Decarboxylase (ldcC) and Response Regulator dr1558

In this study, the response regulator DR1558 from Deinococcus radiodurans was overexpressed in recombinant Corynebacterium glutamicum with lysine decarboxylase (ldcC). The recombinant C. glutamicum strain overexpressing dr1558 and ldcC produced 5.9 g/L of cadaverine by flask cultivation, whereas the control strain overexpressing only ldcC produced 4.5 g/L of cadaverine. To investigate the mechanism underlying the effect of DR1558, the expression levels of genes related to central metabolism and lysine-biosynthesis were analyzed by quantitative-real time polymerase chain reaction. The results showed that phosphoenolpyruvate carboxykinase (pck) was downregulated, and pyruvate kinase (pyk) and other lysine biosynthesis genes were upregulated. Furthermore, in fed-batch fermentation, C. glutamicum coexpressing dr1558 produced 25.14 g/L of cadaverine, a 1.25-fold increase in concentration relative to the control. These results suggested that the heterologous expression of dr1558 may improve the production of biorefinery products by recombinant C. glutamicum.