Transport and metabolic engineering of the cell factory Corynebacterium glutamicum.

Corynebacterium glutamicum has a long and successful history in the biotechnological production of the amino acids l-glutamate and l-lysine. In the recent years, C. glutamicum has been engineered for the production of a broad catalog of value-added compounds including organic acids, vitamins, terpenoids and proteins. Moreover, this bacterium has been engineered to realize a flexible carbon source concept enabling product formation from various second generation feedstocks without competing uses in human and animal nutrition. In this review, we highlight transport engineering to improve product export and substrate uptake or to avoid loss of intermediates by excretion as well as the application of new metabolic engineering concepts for C. glutamicum strain development including the use of designed synthetic Escherichiacoli-C. glutamicum consortia. As examples, pathway extension of l-lysine and l-glutamate biosynthesis to produce derived value-added chemicals is described. The described examples of C. glutamicum strain engineering reflect strategies to cope with the increasing complexity of biotechnological processes that are required for successful applications in the bioeconomy.