l-Ornithine is a non-protein amino acid with extensive applications in medicine and the food industry. Currently, l-ornithine is produced by microbial fermentation; however, this process needs to be further improved in terms of l-ornithine productivity and cost reduction. In this study, overexpression of LysE was observed to increase l-ornithine production in engineered Corynebacterium glutamicum S9114. To overcome the drawbacks of using a plasmid to express LysE, P