Abstract
A threonine-auxotroph of Escherichia coli was found to accumulate a significant amount of an amino acid in the culture broth. The amino acid was isolated in crystalline form from the culture broth and was identified as L-homoserine. The cultural conditions of L-homoserine production by the organism was investigated. The concentration of L-threonine in the medium influenced remarkably on the accumulation of L-homoserine by the organism. L-Homoserine accumulation was maximum at a suboptimum concentration, about 300 micrograms of L-threonine per milliliter, for the growth of the organism. The addtion of L-isoleucine or α-aminobutyric acid to the medium stimulated L-homoserine accumulation. About 4 milligrams of L-homoserine per milliliter accumulated with the medium containing glycerol (5%).
