IMPROVED PRODUCTION OF RIBOFLAVIN

摘要

PROBLEM TO BE SOLVED: To secrete and produce a riboflavin useful for preparing a food or a composition for a feed by culturing a specific recombinant bacterium transformed with three or four vectors. SOLUTION: A recombinant bacterium transformed with three or four vectors or DNA sequences is grown under proper growth conditions. Two of the vectors or DNA sequences respectively comprises a DNA sequence capable of coding riboflavin synthase activities of Bacillus subtilis (or a substantially homologous DNA sequence) and one or more transcription elements and further the third and/or the fourth vector or DNA sequence comprises a DNA sequence coding a ribA gene product of the Bacillus subtilis (or the substantially homologous DNA sequence) and optionally a transcription element. One or plural copies of the vectors are integrated into three of four different sites of a chromosome of a bacterium with the transcription elements.