Production of L-arginine by fermentation using genetically engineered Escherichia coli

Nitrogen leakage in soil is a major environmental threat as it results in drinking water contamination, eutrophication and soil acidification. Excessive use of plant fertilizers containing inorganic nitrogen greatly contributes to this problem due to poor nitrogen absorption by plant roots. However amino acids, which contain organic nitrogen, are much more efficiently taken up by plants. This makes L-arginine, the most nitrogen-rich amino acid, a promising alternative nitrogen source in plant fertilizers.

The development of a sustainable method to produce L-arginine is therefore of great interest. Various microorganisms, including Escherichia coli, naturally produce this amino acid. Favorable traits of Escherichia coli, such as fast growth and easy handling in combination with a well characterized metabolism and molecular tools available for genetic engineering, make it an attractive candidate for the production of L-arginine by fermentation.

In this study, fermentation performances of nine different Escherichia coli strains modified for enhanced L-arginine production were compared. The strains displayed different behaviors, producing between 2 and 14 g/L of L-arginine with a productivity ranging from 0.1 to 0.6 g/L/h, thereby demonstrating the potential of the process.