Engineered <i>Vibrio natriegens</i> with a Toxin–Antitoxin System for High-Productivity Biotransformation of <scp>l</scp>-Lysine to Cadaverine

<i>Vibrio natriegens</i>, a fast-growing bacterium, is an emerging chassis of next-generation industrial biotechnology capable of thriving under open and continuous culture conditions. Cadaverine, a valuable industrial C5 platform chemical, has various chemical and biological activities. This study found that <i>V. natriegens</i> exhibited superior tolerance to lysine, the substrate of cadaverine production. For the first time, a cadaverine synthesis pathway was introduced into <i>V. natriegens</i> for whole-cell catalysis of cadaverine from lysine. A high-efficiency cadaverine-producing strain harboring a toxin-antitoxin system, <i>V. natriegens</i> (pSEVA341-pTac-<i>ldcC</i>-pHbpBC-<i>hbpBC</i>) with <i>lysE</i> (PN96_RS17440) inactivation, was constructed. In 7 L bioreactors, the cadaverine titer increased from 115 g/L in the original strain to 158 g/L within 11 h of biotransformation, exhibiting a 37% increase in production. Its productivity reached 14.4 g/L/h with a conversion rate as high as 90%. These results confirm <i>V. natriegens</i> as an exceptional chassis for effective cadaverine bioproduction.