Metabolic engineering of microorganisms for L-Alanine production

Abstract

L-Alanine is extensively used in chemical, food, and medicine industries. Industrial production of L-Alanine has been mainly based on the enzymatic process using petroleum-based L-Aspartic acid as the substrate. L-Alanine production from renewable biomass using microbial fermentation process is an alternative route. Many microorganisms can naturally produce L-Alanine using aminotransferase or L-Alanine dehydrogenase. However, production of L-Alanine using the native strains has been limited due to their low yields and productivities. In this review, metabolic engineering of microorganisms for L-Alanine production was summarized. Among them, the Escherichia coli strains developed by Dr. Lonnie Ingram's group which can produce L-Alanine with anaerobic fermentation process had several advantages, especially having high L-Alanine yield, and it was the first one that realized commercialization. L-Alanine is also the first amino acid that could be industrially produced by anaerobic fermentation.