Effects of an Escherichia coli ilvA Mutant Gene Encoding Feedback-resistant Threonine Deaminase on l-Isoleucine Production by Brevibacterium flavum^†

Abstract

A mutated ilvA gene of Escherichia coli encoding a threonine deaminase that is resistant to feedback inhibition by l-isoleucine was obtained. It was functional in Brevibacterium flavum, and a wild strain of B. flavum into which it was introduced became able to convert exogeneous l-homoserine and l-threonine to l-isoleucine. When it was introduced into a l-threonine-producing B. flavum strain, the transformant accumulated 20 g/liter l-isoleucine from 100 g/liter glucose.

Key words:

• l-isoleucine production
• Escherichia coli
• ilvA
• threonine deaminase
• Brevibacterium flavum