Dsm IP Assets B.v.

Roche Vitamins Inc.

Keiko Ichikawa

Tatsuo Hoshino

Masaaki Tazoe

Yoichiro Nagatani

The present invention relates to a DNA encoding a novel flavin adenine dinucleotide (FAD)-dependent D-erythronate 4-phosphate (EN4P) dehydrogenase originated from, which is involved in vitamin B6 biosynthesis, and a recombinant microorganism transformed with a vector having the DNA. It also relates to a process for production of vitamin B6 by using the recombinant microorganism. 'Vitamin B6' as used in this invention includes pyridoxol (PN), pyridoxal and pyridoxamine. Vitamin B6 is a vitamin indispensable to human beings or other animals, and is used as a raw material of medicines or as feed additives.

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Disclosed is a mutant of a recombinant microorganism of the genuscapable of producing vitamin Bhaving a recombinant plasmid with pdxJ gene that acquired histidine requirement of glycine resistance, or its combination thereof.

Process for producing vitamin B6

A purified vitamin B-phosphate phosphatase (VB6PP), having the following physico-chemical properties: a) Molecular weight: 29,000&#xb1;5,000 (consisting of a monomer having a molecular weight of 29,000&#xb1;5,000); b) Co-factor: Mn, Mg, Co, Sn, or Ni; c) Substrate specificity: active on pyridoxol 5'-phosphate, pyridoxal 5&#x2032;-phosphate and pyridoxamine 5&#x2032;-phosphate; d) Optimum temperature: 30&#x2013;400&#xb0; C. at pH 7.5; and e) Optimum pH: 7.0&#x2013;8.0 is disclosed. Also disclosed are a process for producing VB6PP from a microorganism belonging to the genuscapable of producing VB6PP, a process for producing vitamin Bfrom vitamin B-phosphate (VB6P) utilizing VB6PP, and a cell-free extract of a microorganism belonging to the genuscapable of producing VB6PP.

A process for producting vitamin B.sub.6 comprises cultivating a microorganism belonging to the genus Rhizobium and being capable of producing vitamin B.sub.6 in a culture medium under aerobic conditions, and separating the resulting vitamin B.sub.6 from the fermentation broth. As well as containing assimilable carbon sources, digestible nitrogen sources, inorganic salts and other nutrients necessary for the growth of the microorganism, the culture medium preferably additionally contains pyruvate, D-glyceraldehyde, glycolaldehyde, glycine, 1-deoxy-D-threo-pentulose, 4-hydroxy-L-threonine or a mixture thereof. This process affords high yields of vitamin B.sub.6, a vitamin essential for the nutrition of animals, plants and microorganisms and useful as a medicine and in foodstuffs.

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Kanagawa-ken, Japan

Keiko Ichikawa