Claims
- 1. A process for preparing riboflavin, which comprises steps of culturing in a cultivation medium (1) a purine-requiring revertant yeast, Saccharomyces cerevisiae TR-29, which is resistant to 3-amino-1,2,4-triazole and is derived from a riboflavin-producing parent yeast strain, Saccharomyces cerevisiae TP-1010, which has a purine requirement and is resistant to 3-amino-1,2,4-triazole, or (2) Saccharomyces cerevisiae NH-268, which is an ammonium ion and 3-amino-1,2,4-triazole-resistant variant derived from Saccharomyces cerevisiae TR-29, and collecting the produced riboflavin.
- 2. A process as claimed in claim 1, in which Saccharomyces cerevisiae TR-29 is used.
- 3. A process as claimed in claim 1, in which Saccharomyces cerevisiae NH-268 is used.
- 4. A process as claimed in claim 2, in which said Saccharomyces cerevisiae TR-29 is obtained by treating Saccharomyces cerevisiae TP-1010 with N-methyl-N'-nitro-N-nitrosoguanidine.
- 5. A process as claimed in claim 3, in which said Saccharomyces cerevisiae NH-268 is obtained by treating Saccharomyces cerevisiae TR-29 with N-methyl-N'-nitro-N-nitrosoguanidine.
- 6. A process as claimed in claim 2, in which said Saccharomyces cerevisiae TR-29 is cultured under aerobic conditions in a culture medium having a pH of 6 to 9 at a temperature of 20.degree. C. to 37.degree. C., said culture medium containing a member selected from the group consisting of a carbon source, a nitrogen source, an inorganic salt, a vitamin, a zinc ion source, and mixtures thereof.
- 7. A process as claimed in claim 3, in which said Saccharomyces cerevisiae NH-268 is cultured under aerobic conditions in a culture medium having a pH of 6 to 9 at a temperature of 20.degree. C. to 37.degree. C., said culture medium containing a member selected from the group consisting of a carbon source, a nitrogen source, an inorganic salt, a vitamin, a zinc ion source, and mixtures thereof.
- 8. A process for preparing riboflavin, which comprises the steps of culturing in a cultivation medium having an ammonium ion concentration of 2000 ppm or above (1) a purine-requiring revertant yeast, Saccharomyces cerevisiae TR-29, which is resistant to 3-amino-1,2,4-triazole and is derived from a riboflavin producing parent yeast strain, Saccharomyces cerevisiae TP-1010, which has a purine requirement and is resistant to 3-amino-1,2,4-triazole, or (2) Saccharomyces cerevisiae NH-268, which is an ammonium ion and 3-amino-1,2,4-triazole-resistant variant derived from Saccharomyces cerevisiae TR-29, and collecting the produced riboflavin.
- 9. A process as claimed in claim 8, in which Saccharomyces cerevisiae TR-29 is used.
- 10. A process as claimed in claim 8, in which Saccharomyces cerevisiae NH-268 is used.
Priority Claims (2)
Number |
Date |
Country |
Kind |
60-167260 |
Jul 1985 |
JPX |
|
61-23486 |
Feb 1986 |
JPX |
|
Parent Case Info
This application is a continuation of U.S. Ser. No. 06/883,796, filed Jul. 9, 1986 now abandoned.
Foreign Referenced Citations (1)
Number |
Date |
Country |
0137226 |
Aug 1984 |
EPX |
Continuations (1)
|
Number |
Date |
Country |
Parent |
883796 |
Jul 1986 |
|