Purification and Characterization of an Antibiotic Substance Produced from Rhizopus oligosporus IFO 8631

Abstract

We obtained a purified antibiotic protein from the submerged cultivation broth of Rhizopus oligosporus IFO 8631 by using CM-Cellulofine chromatography and HPLC.The antibiotic did not show a broad spectrum of activity, but it was very active against some of the Bacillus species, especially against Bacillus subtillis (B.natto) at a very low concentration (less than 1 ppm). It also showed ctivity against other gram-positive bacteria, including Staphylococcus aureus and Streptococcus cremoris. The purified antibiotic was a simple protein of about 5, 500 in molecular weight, the amino acid component being characteristically high in cystine content. This high cystine content contributed to the stability of the antibiotic over a wide pH range and against strong heating (50% of the activity remained after boiling for 1 hr).