---

Threonine

L-threonine is an essential amino acid and is widely used as a feed or food additive. In addition, L-threonine is used as a medical solution or a raw material for a drug synthesis. L-threonine is a second limited amino acid of rice. Lysine, threonine, methionine, cysteine and isoleucine are amino acids derived from aspartate. L-threonine is known to be an essential amino acid applicable as the component of diverse nutritive mixtures of medical use. L-threonine is useful as an immune booster. It degrades into glycine, serine, and glucose. L-Threonine is a wound healer and decreases the harmful effects of aspirin. Besides, L-threonine can be used as an additive to animals' fodder, as well as a reagent for the pharmaceutical and chemical industries and as a growth factor for microorganisms producing some other amino acids, such as L-lysine and L-homoserine. L-threonine is produced by a fermentation process using a mutant strain derived from a wild-type strain of Escherichia coli (E. coli), Corynebacteria sp., Serratia sp., or Providencia sp. Examples of the mutant strain include an amino acid analogue- or drug-resistant mutant strain, or a variety of auxotroph to diaminopimeric acid, methionine, lysine, or isoleucine. 1-threonine is used as a component for, e.g., amino acid transfusion liquid or general amino acid tablets, and as a nutrient.

---