Microbial Transformation of Rifamycin: A Novel Approach to Rifamycin Derivatives

Abstract

Biotransformation of an ansamycin group of antibiotic, rifamycin B (clinically less active) to a more potent antibiotic rifamycin S, involves the action of rifamycin oxidase. The extracellular rifamycin oxidase (RO) from <i>Curvularia lunata </i>offers ease in the process and increased biotransformation potential and yield. Extracellular RO from C. <i>lunata </i>deserves a great future since it shows higher activity and biotransformation potential <i>vis-à-vis </i>intracellular RO from <i>Monocillium </i>and <i>Humicola. </i>Rifamycin S, especiallyamong the derivatives, has been of great commercial significance as a key intermediate for the synthesis of several hundreds of semisynthetic rifamycins.

Besides these, rifamycin S has broad-spectrum activity against <i>Brucella, Chlamydia, Haemophilus, Helicobacter pylori, Legionella </i>and <i>Staphylococcus. </i>It has also emerged as an antituberculosis and antileprosy drug. Chemical conversion of rifamycin B against microbial transformation has been discussed with special emphasis on biotransforming systems, characteristics of rifamycin oxidase and factors influencing the production of rifamycin oxidase and biotransformation of rifamycin B to S.