Process for producing vitamin B12 by the fermentation technique, and vitamin B12-producing microorganism.

摘要

A process for producing vitamin B<Sub>12</Sub> by the fermentation technique which comprises cultivating a vitamin B<Sub>12</Sub>- producing microorganism belonging to the genus Propionibacterium in a culture medium containing a carbon source and a nitrogen source, and collecting vitamin B<Sub>12</Sub> accumulated in the cells of the microorganism; characterized in that
<UnorderedLists id="ula01" listStyle="none"><ListItem>(1) cultivation is carried out while adding a base to maintain the pH at 5 to 7.5, and</ListItem><ListItem>(2) cultivation is carried out while adding a carbon source portionwise to the cultivation system nearly within 10 minutes of adding the base,</ListItem><ListItem>(3) provided that when a vitamin B<Sub>12</Sub>-producing microorganism having resistance to propionic acid is used as the microorganism, the portionwise addition of the carbon source in (2) can be omitted; and a propionic acid-resistant, vitamin B<Sub>12</Sub>-producing microorganism of the genus Proproni- bactenum.</ListItem></UnorderedLists>