producing bacteria L-threonine and a process for preparing L-threonine

Bacteria of the species Escherichia coli, producing L-threonine of which are resistant to beta-hydroxyvaleric amino-acid, wherein said bacteria contain 1) within the coding region of the rpoS gene one (1) stop codon amber type and (2) the corresponding amber suppressor, supE, wherein the stop codon of tipoambar is within the coding region of corresponding rpoS gene to position 33 in the amino acid sequence of the rpoS protein in accordance with SEQ ID No . 2.