Abstract: In a method for producing a target substance utilizing a microorganism comprising culturing the microorganism in a medium to produce and cause accumulation of the target substance in the medium and collecting the target substance, there is used, as the microorganism, a mutant strain or a genetic recombinant strain constructed from a parent strain of the microorganism having a respiratory chain pathway of high energy efficiency and a respiratory chain pathway of low energy efficiency as respiratory chain pathways, and having either one or both of the following characteristics: (A) the respiratory chain pathway of high energy efficiency is enhanced, (B) the respiratory chain pathway of low energy efficiency is deficient.

Abstract: L-amino acids are produced by culturing a microorganism which has an ability to produce the L-amino acid, but has been modified so that expression of the ybjE gene has been enhanced. The L-amino acid is collected from the culture medium or from the microorganism.

Abstract: A bacterium belonging to the genus Escherichia which has an ability to produce L-lysine or L-threonine and which is modified so that a malic enzyme does not function normally in a cell, and a method for producing L-lysine or L-threonine, comprising culturing the bacterium in a medium to produce and cause accumulation of L-lysine or L-threonine, and collecting the L-lysine or L-threonine from the medium.

Abstract: L-amino acids are produced by culturing a microorganism which has an ability to produce the L-amino acid, but has been modified so that expression of the ybjE gene has been enhanced. The L-amino acid is collected from the culture medium or from the microorganism.

Abstract: A bacterium belonging to the genus Escherichia which has an ability to produce L-lysine or L-threonine and which is modified so that a malic enzyme does not function normally in a cell, and a method for producing L-lysine or L-threonine, comprising culturing the bacterium in a medium to produce and cause accumulation of L-lysine or L-threonine, and collecting the L-lysine or L-threonine from the medium.

Abstract: A bacterium belonging to the genus Escherichia which has an ability to produce L-lysine or L-threonine and which is modified so that a malic enzyme does not function normally in a cell, and a method for producing L-lysine or L-threonine, comprising culturing the bacterium in a medium to produce and cause accumulation of L-lysine or L-threonine, and collecting the L-lysine or L-threonine from the medium.

Abstract: L-threonine or L-isoleucine is produced by culturing a bacterium which belongs to the genus Escherichia and has an ability to produce L-threonine or L-isoleucine, and wherein expression of a threonine operon is directed by its native promoter, and from which at least a leader sequence and an attenuator are deleted, in a medium and collecting the L-threonine or L-isoleucine from the medium.

Abstract: A bacterium belonging to the genus Escherichia which has an ability to produce L-lysine or L-threonine and which is modified so that a malic enzyme does not function normally in a cell, and a method for producing L-lysine or L-threonine, comprising culturing the bacterium in a medium to produce and cause accumulation of L-lysine or L-threonine, and collecting the L-lysine or L-threonine from the medium.

Abstract: L-amino acids are produced by culturing a microorganism which has an ability to produce the L-amino acid, but has been modified so that expression of the ybjE gene has been enhanced. The L-amino acid is collected from the culture medium or from the microorganism.

Abstract: A gene coding for fructose phosphotransferase is introduced into a coryneform bacterium having an ability to produce an L-amino acid such as L-lysine or L-glutamic acid to enhance fructose phosphotransferase activity and thereby improve the L-amino acid producing ability.

Abstract: In a method for producing a target substance utilizing a microorganism comprising culturing the microorganism in a medium to produce and accumulate the target substance in the medium and collecting the target substance, there is used, as the microorganism, a mutant strain or a genetic recombinant strain constructed from a parent strain of the microorganism having a respiratory chain pathway of high energy efficiency and a respiratory chain pathway of low energy efficiency as respiratory chain pathways, and having either one or both of the following characteristics:

Abstract: Threonine or isoleucine is be produced by culturing a bacterium belonging to the genus Escherichia, which has an ability to produce L-threonine or L-isoleucine, and in which intracellular phosphoenolpyruvate carboxylase activity and transhydrogenase activity are enhanced, in a medium to produce and accumulate threonine or isoleucine in the medium, and collecting the threonine or isoleucine from the medium.