Biotransformation of cystothiazole A, a myxobacterial antibiotic, into novel derivatives by the mother producer, Cystobacter fuscus

Abstract

The bioconversion of the myxobacterial antibiotic, cystothiazole A, by the antibiotic producer, Cystobacter fuscus, was investigated. In our previous study, an adsorbent resin was added to the fermentation mixture to achieve high productivity of cystothiazole A, the major and most active component. On the other hand, a relative increase in the metabolic derivatives of cystothiazole A was observed when cultured without the resin. Furthermore, when cystothiazole A was externally added to the culture of C. fuscus without the resin, cystothiazole A was rapidly metabolized by the culture to a number of polar metabolic derivatives, among them being novel ones. The identification and structural elucidation of the known and novel derivatives were performed by spectroscopic analyses. Based on the time-dependent production profile and chemical structures of these derivatives, pathways for the conversion of cystothiazole A to the more polar derivatives of this antibiotic by C. fuscus are proposed.