Polyglutamic acid (PGA) is a polymer of the amino acid glutamic acid (GA). Gamma PGA (Poly-γ-glutamic acid, γ-PGA) - the form where the peptide bonds are between the amino group of GA and the carboxyl group at the end of the GA side chain - is a major constituent of the Japanese food nattō. Gamma PGA is formed by bacterial fermentation. Gamma PGA has a wide number of potential uses ranging from food, medicine and cosmeceuticals to water treatment.