Facilitating the enzymatic conversion of lysineto cadaverine in engineered Escherichia coli with metabolic regulation by genes deletion

Cadaverine, also known as 1,5-diaminopentane, is a biogenic amine particularly used for the synthesis of nylon. Cadaverine can be efficiently synthesized through decarboxylation of lysine in microorganisms. However, the respective metabolic pathways in Escherichia coli results in many byproducts in parallel with cadaverine synthesis via genes such as speE, speG, ygjG, and puuA. In this study, nine different types of deletion strains were constructed from the aforementioned four genes to explore their effects on cadaverine production in a T7 promoter based systemic bicistronic cadA-cadB transformed recombinant E. coli. Results show that all the deletion strains could increase cadaverine productivity compared to the deletion-free strain when the culture was supplemented with L-lysine. The cadaverine production from L-lysine with the deletion strains increased 3 folds when compared with that of the deletion-free strain at the cultivation time of 16 h. This indicates that the deletion strain could successfully facilitate lysine consumption and block the undesirable metabolic pathways.