Coproduction of cell-bound and secreted value-added compounds: Simultaneous production of carotenoids and amino acids by Corynebacterium glutamicum

- Coproduction of a cell-bound and a secreted product by engineered C. glutamicum.
- Fermentative coproduction of carotenoids with l-glutamate or l-lysine established.
- Alternative feedstocks as basis for coproduction of l-lysine and β-carotene.
- Astaxanthin and l-lysine produced as two feed supplements from one fermentation.

Corynebacterium glutamicum is used for production of the food and feed amino acids l-glutamate and l-lysine at the million-ton-scale. One feed formulation of l-lysine simply involves spray-drying of the fermentation broth, thus, including secreted l-lysine and C. glutamicum cells which are pigmented by the C50 carotenoid decaprenoxanthin. C. glutamicum has been engineered for overproduction of various compounds including carotenoids. In this study, C. glutamicum was engineered for coproduction of a secreted amino acid with a cell-bound carotenoid. As a proof of principle, coproduction of l-glutamate with the industrially relevant astaxanthin was shown. This strategy was applied to engineer l-lysine overproducing strains for combined overproduction of secreted l-lysine with the cell-bound carotenoids decaprenoxanthin, lycopene, β-carotene, zeaxanthin, canthaxanthin and astaxanthin. By fed-batch fermentation 48 g/L l-lysine and 10 mg/L astaxanthin were coproduced. Moreover, C. glutamicum was engineered for coproduction of l-lysine and β-carotene from xylose and arabinose as alternative feedstocks.

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