| 摘要 |
PURPOSE:To prepare L-tryptophan inexpensively by direction fermantation method, by cultivating a bacterium belonging to the genus Bacillus having sensitivity to L-histidine, and tryptophan analog resistance. CONSTITUTION:A bacterium belonging to the genus Bacillus, having tryptophan analog resistance, capable of producing tryptophan, as a parent strain, is subjected to variation treatment, and a colony is formed on a complete medium. The colony is cultivated in the minimum medium containing L-histidine, and the colony not growing in the medium is selected to give the variant of this invention. The variant is cultivated in a medium containing a carbon source, nitrogen source, inorganic salt, and a very small amount of organic nutrient by shaking culture, to give a large amount of L-tryptophan. The cultivation is carried out at 20-40 deg.C at 5-9pH for 1-4 days. |
