Biosynthesis of rifamycin SV by Amycolatopsis mediterranei MTCC17 in solid cultures

Studies were performed on the production of rifamycin SV, an ansamycin compound, extensively used for curing tuberculosis, leprosy and several other mycobacterial infections, using a strain of Amycolatopsis mediterranei MTCC17 in solid cultures. Wheat bran was employed as a solid substrate. The culture produced 4 g of rifamycin SV/kg of substrate. Pre-treatment of the substrate with dilute HCl was found to increase the yield of rifamycin SV by 300% (from 4 to 12 g x kg of substrate(-1)). Various process parameters were tested to establish the best conditions for the maximum production of the compound and a initial moisture level of 80%, inoculum size of 40%, initial substrate pH of 7.0, incubation temperature of 26 degrees C and a 7 day fermentation period were found to be optimal. Different solvents were used for the extraction of rifamycin SV from the fermented matter and methanol was found to be most suitable. Under optimized conditions, the yield of rifamycin SV further increased from 12 to 32 g x kg of substrate(-1), showing an 8-fold increase from the initial value.