Engineering of Corynebacterium glutamicum for biosynthesis of the pharmaceutically active N-acetyltyramine: establishing and optimizing de novo production.

backgroundN-Acetyltyramine is increasingly recognized for its diverse pharmaceutically relevant properties. In particular, it exhibits antimicrobial activity against multi-drug resistant pathogens, which pose a considerable health challenge. Therefore, the demand for a sustainable and efficient N-acetyltyramine production arises.

resultsHere, we engineered Corynebacterium glutamicum for de novo production of N-acetyltyramine. Heterologous overexpression of different bacterial and insect acetyltransferase genes in a tyramine overproducing strain identified the arylalkylamine N-acetyltransferase from Bombyx mori as the most promising enzyme, resulting in an N-acetyltyramine titer of 5.5 ± 0.3 mM. Design of Experiment-based optimization of the culture medium revealed urea and L-phenylalanine as media components significantly affecting N-acetyltyramine production. Combining media optimization with genetic engineering to balance the expression strength of the genes encoding the L-tyrosine decarboxylase from Levilactobacillus brevis and the arylalkylamine N-acetyltransferase from B. mori increased de novo N-acetyltyramine production to 13.8 ± 0.1 mM (2.5 ± 0.1 g/L). The optimized medium composition was also transferable to the production of other L-tyrosine derivatives, tyramine and tyrosol, increasing their titers by 24% and 44%, respectively. In addition, supplementing the established N-acetyltyramine producing strain with propionate as a second carbon source enabled the production of N-propionyltyramine. To the best of our knowledge, this represents the first report describing biotechnological production of N-propionyltyramine.

conclusionIn this study, de novo N-acetyltyramine production was established and substantially increased through the combined implementation of metabolic engineering and media optimization strategies. The successful transfer of the optimized medium to enhance the production of additional L-tyrosine derivatives underscores the potential of integrating genetic engineering with culture media refinement to improve biotechnological processes.