• Microbiology and Biotechnology Letters
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• v.19 no.6
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• pp.614-618
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• 1991

Antifungal compound, KRF-001, was produced by Bacillus subtilis subsp. krictiensis isolated from soil. Physico-chemical factors affecting cell growth and bioactivity were examined to improve the production yield. Nutrient composition, temperature, pH and phosphate ion concentration were proved to be important factors for the production of KRF-001. Mutation was performed to select high yielding strains. First, mutation was performed with ultra-violet light, and the second mutation process was conducted by MNNG (N-Methyl-N'-nitro-N-nitrosoguanidine) resulting in three high yielding strains.

• Microbiology and Biotechnology Letters
• /
• v.19 no.6
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• pp.598-603
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• 1991

An antifungal mixture of six members (component A to F), KRF-001 produced by Bacillzts subtilis subsp. krictiensis was isolated from the fermentation broth. Molecular weight of component A to F was determined by FAB-MS to be 1042, 1056, 1056, 1070, 1070 and 1084 respectively. Various instrumental analyses (amino acid analysis, GC-MS, $^1H-NMR, ^1HH$ COSY NMR) revealed that the mixture was a homologous cyclic peptide composed of each one mole of glutamine, proline, tyrosine, serine, unusual $\beta$-amino acid and three moles of asparagine. The structural differences of component A to F were found in carbon number and terminal structure of the unusual $\beta$-amino acid. After determination of the sequence and stereochemistry of those amino acids, the tentative structure of KRF-001 was determined.