The ingredients used for cell culture media applications during biopharmaceutical production have transitioned in recent years from complex animal-derived compositions to well-defined chemical compositions. This evolution in the nature and quality of animal-origin-free ingredients has helped to increase the overall safety, consistency and performance of cell culture media. However, emerging application requirements for the purity, stability, consistency and supply security of cell culture ingredients continue to influence biopharmaceutical companies in their selection processes. Increasingly, the goal of biopharma companies has been to partner with preferred global cell culture ingredient suppliers that have a broad portfolio, robust processes and trusted manufacturing sites. Because amino acids function as protein building blocks, they are essential ingredients of cell culture media. Therefore, strong backward integration for amino acids is also strongly desirable.
Enhancing the solubility of L-Tyrosine in cell culture media applications
The stability and solubility limitations of many amino acids such as L-Tyrosine and L-Glutamine has represented a major barrier to the further improvement of cell culture media applications. However, these challenges can be overcome with the replacement of such amino acids with dipeptides.
L-Tyrosine is an important amino acid for protein synthesis and cellular metabolism. However, it can exhibit poor solubility in water and media, and cannot be prepared at the desired concentrations at neutral pH. While the use of extreme pH values is often used to increase solubility, the process can face many drawbacks. To solve this challenge, Evonik has developed a selection of dipeptides to improve the solubility of L-Tyrosine. cQrex® GY (glycyl-L-tyrosine) and AY (L-alanyl-L-tyrosine) increase the solubility at neutral pH by up to 50 times compared to free L-Tyrosine. Because these peptides are efficiently taken up and metabolized by the cell, full replacement of L-Tyrosine is possible.
Enhancing the stability of L-Glutamine in cell culture media applications
L-Glutamine is a well-known example of an amino acid that exhibits limited chemical stability in water or equivalent solutions. This tendency to easily degrade can lead to elevated levels of ammonia and glutamic acid or pyroglutamate, which have a detrimental impact on cell culture performance, product quality and long-term stability in liquid media or feeds. Evonik has created a selection of dipeptides to stabilize L-glutamine, including cQrex® AQ (L-Alanyl-L-glutamine), GQ (Glycyl-L-glutamine), and AAQ (N-Acetyl-L-alanyl-L-glutamine) that are used to replace free glutamine in basal media or feeds. Glycyl-L-glutamine (cQrex® GQ) and L-alanyl-L-glutamine (cQrex® AQ) are both chemically stable and highly bioavailable forms of L-glutamine that have a long history across a range of cell culture applications.
Enhancing the stability of L-Cysteine in cell culture media applications
L-Cysteine can play an important role in the protection of cells from oxidative stress. However, is highly reactive, readily forms dimeric L-cystine with reduced solubility in water, which will often precipitate in neutral pH feeds. cQrex® AC (N,N'-di-L-Alanyl-L-cystine) is a highly soluble, stable and bioavailable form of L-Cysteine. It can increase the solubility of L-cystine by more than 20 times and is ideal for increasing the concentration of L-cysteine / L-cystine in basal media as well as in the preparation of highly concentrated feeds. This dipeptide can be efficiently taken up as a source of cysteine/cystine, and act as a stabilizer to prevent L-cysteine precipitation caused by its oxidization in the medium.
Other cQrex® cell culture ingredient solutions to further improve application performance
The opportunity to utilize Evonik’s range of dipeptides to either partially or fully replace amino acids in basal, feed and perfusion media can also help to increase yields and generate more stable and robust processes. In addition to these dipeptides, Evonik also offers a selection of additives that can further help to enhance media processes.
These additives include:
- cQrex® Carnosine, which is also a dipeptide, that can protect against oxidative stress, and prevent or reverse senescence in primary and stem cell cultivation.
- cQrex® AKG (α-ketoglutaric acid), which is a titer-enhancing additive that can improve energy supply and protect cells against oxidative damage.