Strains and method for the production of methionine

摘要

The present invention relates to a method for the production of methionine using modified strains with attenuated transformation of threonine. This can be achieved by reducing threonine transformation into glycine, and/or by reducing its transformation to α-ketobutyrate. The invention also concerns the modified strains with attenuated transformation of threonine.

主权项

1. A method for the production of methionine, its precursors or derivatives S-acyl methionine (SAM) and N-acyl methionine (NAM) in a fermentative process comprising:
culturing a modified microorganism, overexpressing homoserine succinyltransferase alleles with reduced feedback sensitivity to S-acyl methionine (SAM) and methionine, in an appropriate culture medium comprising a source of carbon, a source of sulphur and a source of nitrogen, and recovering methionine, and/or its said precursors or derivatives, from said culture medium,wherein said microorganism is modified by mutating its serine deaminase (sdaA) gene sequence in position 158 with a G nucleotide compared to the wild-type sdaA gene from E. coli (SEQ ID NO: 21), thereby increasing serine availability in the microorganism.