In the upstream fermentation and downstream purification of recombinant proteins, monoclonal antibodies (mAbs), and peptide hormones (e.g. insulin), acetates are essential processing aids.
Fermentation and pH control
In microbial fermentations, ammonium acetate and potassium acetate serve a dual purpose.
They act as highly bioavailable, low-salinity sources of nitrogen and potassium, while the acetate anion functions as a readily metabolizable carbon source.
Acetate buffer systems, primarily based on sodium acetate trihydrate, are widely used to maintain precise pH control in fermenters, preventing acid-induced metabolic stress on the expression hosts.
Protein purification and chromatography
During the purification of therapeutic proteins, such as hormones, sodium acetate trihydrate and ammonium acetate are standard components of mobile phases.
In cation-exchange chromatography, an acetic acid/sodium acetate buffer establishes the precisely controlled acidic pH required to ensure that the target protein carries a net positive charge, allowing it to bind to the column resin while impurities are washed away.
Furthermore, ammonium acetate is highly valued in the purification of synthetic peptides and hormones because of its volatility. During subsequent freeze-drying (lyophilization) or vacuum evaporation, the buffer sublimes completely into ammonia and acetic acid vapours, leaving behind a highly pure, salt-free API cake.
