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Preparing L-amino acids, particularly L-threonine, for use in pharmaceutical and in food industries, comprises employing the microorganisms of the Enterobacteriaceae family for fermentation in which the poxB gene is attenuated
Preparing L-amino acids, particularly L-threonine, for use in pharmaceutical and in food industries, comprises employing the microorganisms of the Enterobacteriaceae family for fermentation in which the poxB gene is attenuated
Fermentative preparation of L-amino acids, particularly L-threonine, comprises fermentation of the microorganisms of the Enterobacteriaceae family which produce the desired L-amino acids and in which the poxB gene or nucleotide sequences which code for it are attenuated, preferably eliminated. The fermentative preparation of L-amino acids, particularly L-threonine, comprises: (a) fermentation of the microorganisms of the Enterobacteriaceae family which produce the desired L-amino acids and in which the poxB gene of nucleotide sequences which code for it are attenuated, preferably eliminated; (b) concentration of the L-amino acid in the medium or in the cells of the bacteria; and (c) isolation of the L-amino acid. Independent claims are also included for the following: (1) a microorganism of the Enterobacteriaceae family which produces L-amino acids in which the poxB gene or nucleotide sequences which code for it are attenuated, particularly eliminated, and which have a resistance to alpha -amino- beta -hydroxyvaleric acid and optionally a compensatable partial need for L-isoleucine; (2) the Escherichia coli K-12 strain MG244 DELTA posB deposited at the Deutsche Sammlung fur Mikroorganismen und Zellkulturen (DSMZ, German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany) under number DSM 13762; (3) plasmid pMAK705 DELTA poxB which contains parts of the 5' and 3' region of the poxB gene comprising a sequence of 1454 base pairs (bp), given in the specification; (4) plasmids pMW218gdhA and pMW219rhtC fully described in the specification; (5) an isolated polynucleotide from microorganisms of the Enterobacteriaceae family containing a polynucleotide sequence which codes for the 5' and 3' region of the poxB gene comprising a sequence of 1448 bp, given in the specification, as a constituent of plasmids for position-specific mutagenesis of the poxB gene; and (6) a strain of the Enterobacteriaceae family, which produces L-threonine and contains a mutation in the poxB gene corresponding to a defined 1448 bp sequence, given in the specification.
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