Degradation Products of Tryptophan in Cell Culture Media: Contribution to Color and Toxicity

Abstract

Biomanufacturing processes may be optimized by storing cell culture media at room temperature, but this is currently limited by their instability and change in color upon long-term storage. This study demonstrates that one of the critical contributing factors toward media browning is tryptophan. LC-MS technology was utilized to identify tryptophan degradation products, which are likely formed primarily from oxidation reactions. Several of the identified compounds were shown to contribute significantly to color in solutions but also to exhibit toxicity against CHO cells. A cell-culture-compatible antioxidant, a-ketoglutaric acid, was found to be an efficient cell culture media additive for stabilizing components against degradation, inhibiting the browning of media formulations, and decreasing ammonia production, thus providing a viable method for developing room-temperature stable cell culture media.

Impact of preparation pH and temperature on amino acid stability of highly concentrated cell culture feed media

“…1). Moreover, storage at RT resulted in changes to the color of the medium, likely indicating oxidation 2,14,22 . Nonenzymatic reactions with reducing sugars (such as Maillard reaction) could also cause a significant AA decrease.…”

“…Moreover, storage at RT resulted in changes to the color of the medium, likely indicating oxidation. 2,14,22 Nonenzymatic reactions with reducing sugars (such as Maillard reaction) could also cause a significant AA decrease. Maillard reactions may happen at RT 23 with the increasing intensity at higher temperatures and pH values, 24 and this is consistent with the observations made in this study (Figs 2 and 4).…”

Tryptophan in Nutrition and Health

“…This Special Issue contains seven reviews and nine original research articles that conclusively demonstrate developmental programming and reprogramming [ 1 ], uniqueness of tryptophan [ 2 ], the role of 5-hydroxytryptophan [ 3 ], tryptophan AhR-ligands in the skin [ 4 ], the impacts of tryptophan metabolites on coronavirus pathophysiology [ 5 ], tryptophan metabolism in organ transplantation [ 6 ], gut-derived 5-hydroxytryptamin [ 7 ], effects of AhR-ligands on melanoma cells [ 8 ], effects of stress and escitalopram on genes of the tryptophan catabolite pathways [ 9 ], formation of tryptophan derivatives by Saccharomyces cerevisiae [ 10 ], the relationship between tryptophan-related fluorescence in urine and malignant melanoma [ 11 ], the effects of tryptophan supplementation on milk protein synthesis and energy metabolism [ 12 ], the induction of tryptophan deficiency and dysbiosis with associated increased systemic inflammation in aged mice [ 13 ], the effects of tyrosine and tryptophan supplementation on diet-induced obesity [ 14 ], degradation products of tryptophan [ 15 ], and the molecular interactions of nitrofurantoin and albumin [ 16 ].…”