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This is a complex question. There are direct effects and indirect effects. The direct effects are mostly driven by sugar mix, specifically what kind of sugar (ex. glucose or galactose) and what form it is in. Additionally, there are many indirect effects that control the environment. The amount of a certain amino acid such as glutamic acid in combination with glucose levels can lead to higher lactic acid and a pH change, which will affect the glycosylation pattern. Further, if a base is used to increase the pH, then the osmolarity will increase, and that can also influence the glycosylation pattern. There are amino acids, such as glutamine, that are more likely to lead to increases in ammonia, which will also influence the addition of glycans. Outside of the standard media ingredients, scientists have used peptones from plants or yeast to influence the glycosylation patterns with varying results. Another approach is to supplement with cholesterol and free fatty acids to increase the efficiency and functionality of the ER and Golgi. The range of potential influencers on post-translational modification both direct and indirect are part of the reason for the complexity that is seen in this field.