Patent ID: 7989189

Claim:
A method for producing riboflavin, a riboflavin precursor, FMN, FAD, or a derivative thereof comprising: culturing a host cell in a suitable medium, the host cell comprising a polynucleotide comprising a nucleotide sequence which codes for a modified GTP cyclohydrolase II from Bacillus subtilis , wherein (i) the specific activity of the modified enzyme is increased in comparison to the corresponding non-modified enzyme and (ii) the amino acid sequence of the modified enzyme comprises one or more mutations(s) on amino acid position(s) corresponding to positions 261, 270, 276, 279, 308, and/or 347 of SEQ ID NO: 2 and combinations of the one or more mutations(s) thereof such that said modified enzyme includes from 1 to 6 position substitutions selected from: Alanine at an amino acid position corresponding to the position 261, Alanine or Arginine at an amino acid position corresponding to the position 270, Threonine at an amino acid position corresponding to the position 276, Arginine at an amino acid position corresponding to the position 279, Arginine at an amino acid position corresponding to the position 308, and Isoleucine at an amino acid position corresponding to the position 347; said modified enzyme exhibiting at least 98% identity to SEQ ID NO: 2, and optionally separating riboflavin, a riboflavin precursor, FMN, FAD, or a derivative thereof from the medium.