| 摘要 |
PROBLEM TO BE SOLVED: To efficiently obtain L-amino acid by a fermentation method by culturing a bacterium in which aspartokinase III gene derived from Escherichia coli bacterium having variation from which feed back inhibition by L-lysin is released is introduced. SOLUTION: A bacterium belonging to the genus Escherichia and introducing the following DNA therein is cultured in fermentation culture medium and L-amino acid is produced and accumulated in culture products and collected from the cultured products to efficiently provide the objective L-amino acid. The DNA is a DNA coding aspartokinase III of bacterium of the genus Escherichia and containing a gene having variation releasing feed back inhibition of the enzyme by lysine in a coding region, in which the variation is performed by each replacing 318th Met and 323rd Gly, 325th Leu and 347th Val, 323rd Gly and 347th Val, etc., of aspartokinase with other amino acid residue, and the DNA is preferably a recombinant DNA obtained by being connected to a vector DNA capable of carrying out autonomous replication in a cell of bacterium belonging to the genus Escherichia. |
