Abstract:l-threonine is one of the eight essential amino acids that cannot be synthesized by the human body and must be taken from food. It is an important component of protein synthesis and is widely used in food, feed, medicine and other fields. At present, Escherichia coli can achieve a high threonine yield in fermentation, being the main bacterium used for industrial production of threonine. With the development of metabolic engineering, the modification of strains is no longer limited to mutagenesis, and the directed modification of strains greatly improves the production of l-threonine, facilitating the development of the l-threonine industry. This paper introduces the physicochemical properties and synthesis pathway of l-threonine and reviews the achievements in improving l-threonine production by metabolic engineering, aiming to enrich the knowledge about the modification of Escherichia coli for efficient synthesis of threonine.
