Antibiotics such as rifamycin are broad-spectrum antimicrobial drugs used in large-scale worldwide as human medicine towards controlling diseases. Amycolatopsis mediterranei strain which produces this antibiotic was earlier used in submerged fermentation yielded lower amounts of rifamycin. By employing cheaper agro-industrial by-products, we produced upto 20 g rifamycin SV per Kg dry substrate used under optimized solid state fermentation conditions. Keeping in view, the role of rifamycin in meeting the medical demands of world's increasing population; we successfully used an improved strain on cheaper substrates with optimized fermentation parameters and achieved a 5-fold improvement in rifamycin SV production.

Due to fast depletion of fossil fuels in the modern world, bioethanol usage as an alternate energy source is the need of the hour. For the first time, we report bioethanol production by Candida albicans via direct conversion of starchy biomass into ethanol along with enhanced starch-hydrolysing capacity and ethanol conversion ratio. So far, C. albicans was dealt in the field of clinical pathology, but here we successfully employed this organism to produce bioethanol from starchy agri-substrates. Optimizing fermentation parameters and improving the microbial strains through successive mutagenesis can improve the end product yield.

Rifamycin is a broad-spectrum antimicrobial drug produced commercially by submerged fermentation where the yields are far less in comparison to its demand in human drug therapy. Addressing the need, sequential mutational strain improvement was carried using UV and EtBr that resulted in improved strain yielding rifamycin SV up to 4.32 g/L. Further optimization of six important fermentation factors was followed which include temperature, agitation, inoculum level, period of fermentation, inorganic nitrogen source and amino acids. For the first time, we report a maximum yield of 5.32 g/L of rifamycin SV. Among the amino acids, proline known for its slowest assimilation by Amycolatopsis mediterranei produced the highest improvement in antibiotic yields. Following mutational strain improvement and process optimization, a total of 3.8-fold increase in antibiotic titre was achieved. Following a conventional procedure of mutational strain improvement, highest yield of rifamycin SV was reported by optimizing submerged fermentation process.

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