摘要:
A magnetic head includes core blocks having a medium sliding surface formed on one surface of the core blocks, the medium sliding surface having a slender convex curved shape formed along a sliding direction of a recording medium from the upstream side of the sliding direction to the downstream side, and the medium sliding surface having a magnetic gap formed thereon, wherein the medium sliding surface is shaped along a longitudinal direction thereof like a circular arc with a radius of curvature R while being shaped along a width direction like a circular arc with a radius of curvature r, which is smaller than the radius of curvature R, so that the radius of curvature r is continuously reduced with closer distance to the downstream end of the recording medium sliding direction from a vicinity of the magnetic gap, so that by employing the above magnetic head, a long life magnetic head with small damage due to foreign material adhesion as well as small abrasion can be provided.
摘要:
A method for producing an L-amino acid, which comprises inserting a gene which codes for an enzyme which is utilized on the route of biosynthesis of an L-amino acid product into one of at least two plasmid vectors which have compatible replicating origins different from each other, inserting a second gene which codes for an enzyme different from the first enzyme on the route of biosynthesis of the L-amino acid into a second of the plasmid vectors; introducing the thus obtained recombinant plasmids into a strain of Coryneform bacteria; and culturing the thus transformed strain which is capable of producing the L-amino acid, said two enzymes being highly rate determining enzymes for the biosynthesis of L-amino acid.
摘要:
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.
摘要:
A microorganism is cultured in a medium, and is able to produce one or two or more kinds of L-amino acids including L-glutamic acid, L-glutamine, L-proline, L-ornithine, L-citrulline and L-arginine, and is modified to increase α-ketoglutarate synthase activity. The L-amino acids are collected from the medium or the cells.
摘要:
An organic acid is produced by allowing a bacterium which has an ability to produce an organic acid and has been modified so that expression of yidE gene is enhanced, or a product obtained by processing the bacterium, to act on an organic raw material in a reaction mixture containing carbonate ions, bicarbonate ions, or carbon dioxide gas to produce the organic acid, and collecting the organic acid.
摘要:
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.
摘要:
A microorganism is provided which can metabolize a carbon source at a specific pH in a liquid medium containing L-glutamic acid at a saturation concentration and the carbon source, and which has ability to accumulate L-glutamic acid in an amount exceeding the amount corresponding to the saturation concentration in the liquid medium at the pH. Also provided is a method for producing L-glutamic acid by fermentation, which comprises culturing the microorganism in a liquid medium of which pH is adjusted to a pH at which L-glutamic acid is precipitated, to produce and accumulate L-glutamic acid and precipitate L-glutamic acid in the medium.
摘要:
A novel aldolase is described. 4-hydroxy-3-methyl-2-keto-pentanoic acid, which is useful as an intermediate in the synthesis of 4-hydroxy-L-isoleucine, may be synthesized from acetaldehyde and α-ketobutyric acid using a novel aldolase, which is derived from the genus Arthrobacter.
摘要:
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.
摘要:
An L-amino acid is produced by culturing an Enterobacteriaceae which is able to produce an L-amino acid in a medium containing glycerol, especially crude glycerol, as the carbon source to produce and accumulate the L-amino acid in the culture, and collecting the L-amino acid from the culture.