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 plurality of primer sets are designed based on a region where conservation at the amino acid level is observed among various microorganisms for known gene sequences corresponding to a gene coding for an enzyme of the L-amino acid biosynthetic pathway derived from Corynebacterium thermoaminogenes, preferably an enzyme that functions at a higher temperature compared with that of Corynebacterium glutamicum. PCR is performed by using the primers and chromosomal DNA of Corynebacterium thermoaminogenes as a template. The primers with which an amplification fragment has been obtained are used as primers for screening to select a clone containing a target DNA fragment from a plasmid library of chromosomal DNA of Corynebacterium thermoaminogenes.
摘要:
A method for producing L-glutamic acid which comprises culturing a microorganism belonging to the genus Klebsiella, Erwinia or Pantoea and having an ability to produce L-glutamic acid in a culture medium, and collecting produced L-glutamic acid from the culture medium. The microbial strain used is preferably a strain which decreases in or is deficient in an activity of an enzyme catalyzing a reaction branching from a pathway for L-glutamic acid biosynthesis and producing a compound other than L-glutamic acid, or a strain which increase in an activity of an enzyme catalyzing a reaction for L-glutamic acid biosynthesis.
摘要:
L-Glutamic acid is produced by culturing in a liquid culture medium a microorganism belonging to the genus Enterobacter or Serratia. Further, the microorganism having an ability to produce L-glutamic acid, which increases in an activity of enzyme catalyzing a reaction for L-glutamic acid biosynthesis, or which decreases in or is deficient in an activity of an enzyme catalyzing a reaction branching from a pathway for L-glutamic acid biosynthesis and producing a compound other than L-glutamic acid, and collecting produced L-glutamic acid from the culture medium.
摘要:
A coryneform bacterium in which a DNA fragment is incorporated into its chromosome is prepared by (a) obtaining a recombinant plasmid through ligation of a DNA fragment having a sequence homologous to a gene present on a chromosome of a coryneform bacterium to a plasmid that has a wild-type replication control region segment of a particular nucleotide sequence including a mutation and is autonomously replicable in a coryneform bacterium cell at a culture temperature lower than 31° C. but not autonomously replicable in the cell at a temperature of 31° C. or higher, (b) introducing the recombinant plasmid into the coryneform bacterium cell, (c) culturing the bacterium at a temperature of 31° C. or higher, (d) causing homologous recombination between the DNA fragment and the gene present on the chromosome of the coryneform bacterium and having a sequence homologous to the DNA fragment, and (e) selecting a coryneform bacterium in which the DNA fragment is incorporated into its chromosome. According to the present invention, there is provided a method for efficiently modifying genetic traits of a host in a short period of time by obtaining a temperature sensitive plasmid from a plasmid not exhibiting homology with already reported temperature sensitive plasmids or not exhibiting incompatibility therewith.
摘要:
A method for producing L-glutamic acid which comprises culturing a microorganism belonging to the genus Klebsiella, Erwinia or Pantoea and having an ability to produce L-glutamic acid in a culture medium, and collecting produced L-glutamic acid from the culture medium. The microbial strain used is preferably a strain which decreases in or is deficient in an activity of an enzyme catalyzing a reaction branching from a pathway for L-glutamic acid biosynthesis and producing a compound other than L-glutamic acid, or a strain which increase in an activity of an enzyme catalyzing a reaction for L-glutamic acid biosynthesis.
摘要:
A mutant of the genus Escherichia is described, the .alpha.-ketoglutarate dehydrogenase activity of which is deficient or reduced, and/or the phosphoenol pyruvate carboxylase and/or glutamate dehydrogenase activities of which are amplified. The mutant is useful in the fermentative production of L-glutamic acid.
摘要:
A composite plasmid which comprises (A) a drive-unit region derived from a plasmid a capable of propagating in a Coryneform glutamic acid-producing bacterium, and (B) a gene fragment derived from a plasmid b capable of propagating in Escherichia coli or Bacillus subtilis and having at least a region expressing drug resistance.