Abstract: An L-amino acid is produced by culturing a microorganism of the family Enterobacteriaceae which has the ability to produce an L-amino acid and which has been modified so as to increase the expression of the evgA gene, the gadE gene, and/or the ydeO gene. These genes encode a transcription factor involved in the EvgAS two-component system regulon. The culture takes place in a medium, and the L-amino acid is collected from the medium or cells.

Abstract: The present invention provides a method for producing an L-amino acid by fermentation by culturing a microorganism having an L-amino acid-producing ability in a liquid medium to precipitate the L-amino acid, wherein a polymer such as a water-soluble cellulose derivative, a water-soluble polyvinyl compound, a polar organic solvent-soluble polyvinyl compound, a water-soluble starch derivative, an alginic acid salt, and a polyacrylic acid salt is added to the medium.

Abstract: A method for intracellular metabolic flux analysis comprising (a) culturing cells in a medium not containing any isotope-labeled substrate to a target phase of the metabolic flux analysis, (b) adding an isotope-labeled substrate to the medium, and continuing culture and collecting samples from the medium in time course, (c) measuring isotope distribution in an intracellular metabolite contained in the samples collected in time course, (d) performing a regression analysis for measured data and calculating an isotope distribution ratio in a steady state, and (e) analyzing a metabolic flux of the cultured cells by using the calculated isotope distribution ratio.

Abstract: A bacterium which belongs to the Enterobacteriaceae family and has an ability to produce an L-amino acid such as L-lysine, L-threonine and L-tryptophan and is modified to enhance glutamic acid decarboxylase activity is cultured in a medium to produce and accumulate the L-amino acid in the medium or cells of the bacterium. Then, the L-amino acid is collected from the medium or the cells.

Abstract: An L-amino acid can be produced by culturing an L-amino acid-producing bacterium which belongs to the Enterobacteriaceae family and which has been modified so that the expression of a yggG gene is enhanced.

Abstract: A method is described for producing an L-amino acid or a nucleic acid by culturing a microorganism having an ability to produce the L-amino acid or nucleic acid in a liquid medium in a fermentation tank containing a stirring impeller, and optionally adding seed crystals to the medium as required to produce and accumulate crystals of the L-amino acid or nucleic acid in the medium, and collecting crystals of the L-amino acid or nucleic acid from the culture. The power density of the stirring impeller is controlled to be 2.4 kW/m3 or lower after either precipitation of the crystals or addition of the seed crystals.

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 metabolic flux affecting substance production using cells is determined by 1) creating a stoichiometric matrix based on formulas of biochemical reactions from a substrate through a desired produced substance, 2) selecting the same number of independent metabolic fluxes from all metabolic fluxes as the degree of freedom of the stoichiometric matrix as free fluxes, 3) creating a sufficient number of random combinations of the free fluxes for a statistical analysis and calculating a metabolic flux distribution from each created combination based on the stoichiometric matrix, 4) obtaining a regression equation including a minimum number of free fluxes that shows a correlation with substance production from the calculated metabolic flux distributions by a multivariate statistical analysis, and 5) determining at least one metabolic flux affecting substance production based on a coefficient in the obtained regression equation.

Abstract: A method is described for producing an L-amino acid or a nucleic acid by culturing a microorganism having an ability to produce the L-amino acid or nucleic acid in a liquid medium in a fermentation tank containing a stirring impeller, and optionally adding seed crystals to the medium as required to produce and accumulate crystals of the L-amino acid or nucleic acid in the medium, and collecting crystals of the L-amino acid or nucleic acid from the culture. The power density of the stirring impeller is controlled to be 2.4 kW/m3 or lower after either precipitation of the crystals or addition of the seed crystals.

Abstract: An L-amino acid can be produced by culturing an L-amino acid-producing bacterium which belongs to the Enterobacteriaceae family and which has been modified so that the expression of a yggG gene is enhanced.

Abstract: An L-amino acid is produced by culturing a microorganism of the family Enterobacteriaceae which has the ability to produce an L-amino acid and which has been modified so as to increase the expression of the evgA gene, the gadE gene, and/or the ydeO gene. These genes encode a transcription factor involved in the EvgAS two-component system regulon. The culture takes place in a medium, and the L-amino acid is collected from the medium or cells.

Abstract: The present invention provides a method for producing an L-amino acid by fermentation by culturing a microorganism having an L-amino acid-producing ability in a liquid medium to precipitate the L-amino acid, wherein a polymer such as a water-soluble cellulose derivative, a water-soluble polyvinyl compound, a polar organic solvent-soluble polyvinyl compound, a water-soluble starch derivative, an alginic acid salt, and a polyacrylic acid salt is added to the medium.

Abstract: A bacterium which belongs to the Enterobacteriaceae family and has an ability to produce an L-amino acid such as L-lysine, L-threonine and L-tryptophan and is modified to enhance glutamic acid decarboxylase activity is cultured in a medium to produce and accumulate the L-amino acid in the medium or cells of the bacterium. Then, the L-amino acid is collected from the medium or the cells.

Abstract: A method for determining metabolic flux distribution of a cell, which comprises the steps of: 1) creating a stoichiometric matrix based on formulas of biochemical reactions from a substrate to a product, 2) computing a set of vectors of solutions existing in a solution space which the stoichiometric matrix may have, 3) selecting, from the computed set of vectors of solutions, maximum vectors whose vector elements corresponding to respective substances for which input values can be obtained are maximum, and 4) performing linear combination for the selected vectors in accordance with the following equations to obtain a vector representing metabolic flux distribution: S flux = ? i = 1 n ? a i · p i · S ? ( i ) + ? i = 1 n ? b i · q i · A ? ( i ) ( I ) ? i = 1 n ? a i + ? i = 1 n ? b i = 1 ( II ) Sflux: Vector representing metabolic flux distribution to be determined, S(i): Vector selected for substance for which inputted value c

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: A method for simulating a substance production process using cells based on a set of differential equations that represent intracellular metabolites and gene expression comprising including a specific growth rate of cells, expressed as a differential equation, in the set of differential equations; assigning values for parameters in the set of differential equations, wherein at least one of said parameters is represented as a growth rate factor; incorporating in the set of differential equations a formation rate for formation of a cell component, wherein said formation rate is represented as a growth rate factor; incorporating in the set of differential equations an inflow rate of a metabolite taken from outside of the cells and/or an outflow rate of a metabolite excreted out of the cells, wherein said inflow/outflow rates are represented as a growth rate factor; solving the set of differential equations; and generating data representative of the substance-production process.

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 metabolic flux affecting substance production using cells is determined by 1) creating a stoichiometric matrix based on formulas of biochemical reactions from a substrate through a desired produced substance, 2) selecting the same number of independent metabolic fluxes from all metabolic fluxes as the degree of freedom of the stoichiometric matrix as free fluxes, 3) creating a sufficient number of random combinations of the free fluxes for a statistical analysis and calculating a metabolic flux distribution from each created combination based on the stoichiometric matrix, 4) obtaining a regression equation including a minimum number of free fluxes that shows a correlation with substance production from the calculated metabolic flux distributions by a multivariate statistical analysis, and 5) determining at least one metabolic flux affecting substance production based on a coefficient in the obtained regression equation.

Abstract: A method for analyzing an intracellular metabolic flux comprising determining the intracellular metabolic flux from analytical values of cells cultured in a medium containing an isotope-labeled substrate as a carbon source on the basis of an intracellular metabolic flux model constructed for the intracellular metabolic flux to be analyzed, wherein (a) influence of an exchange reaction between an intracellular metabolite and a cell component produced by integration of the intracellular metabolite is considered, (b) uptake of a compound in a medium into cells, which compound is identical to an intracellular metabolite and unlabeled with an isotope, is considered, or (c) carbon dioxide used in a fixation reaction is assumed as carbon dioxide produced in a production reaction.