• Microbiology and Biotechnology Letters
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• v.21 no.1
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• pp.47-53
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• 1993

Antibiotics KG-431A and KG-431B were isolated from the fermentation broth of the Clostridium sp. KH-431. As we have shown previously, only KG-431B was successful to recrystallize. These antibiotics showed antimicrobial activities against broad spectrum of bacteria and fungi. KG-431B also showed anticancer activity against some animal tumor cells according to the SRB method. Physico-chemical properties of KG-431B were determined using UV, IR, NMR and Mass spectra. It was identified to be 3-Indole propionic acid and the structure of the KG-431A is currently under investigation.

• Microbiology and Biotechnology Letters
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• v.21 no.1
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• pp.41-46
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• 1993

A strain showing antibiotic activities against various bacteria and fungi was selected from approximately 2,000 microorganisms obtained from soil samples. This strain, designated as KH-431, was identified as a Clostridium sp. by its morphological, physiological and biochemical characteristics. The highest production of the antibiotics was achieved in a fermentation medium containing sorbitol, yeast extract, d-biotin and $CaCl_2$ The antibiotics were isolated from the culture broth by solvent extraction using ethyl acetate, silica gel column chromatography and recrystallization. Two kinds of antibiotics, KG-431A and KG-431B were obtained after the purification procedure, and only KG-431B was successful to recrystallize.