Research Paper Indian Journal of Pharmaceutical Sciences 911 September-October 2018 Essential or intentional stalling of novel drug discovery and development by the pharmaceutical industries due to economic and regulatory obstacles together with the worldwide escalation of emanation and spread of antimicrobial resistance (although a natural phenomenon) constitutes the greatest challenge to global public health today. Microbial natural products appear as the preponderant and promising source for developing future antibiotics [1] . Searching unexplored environments for novel actinomycetes has been the orientation of current antibiotic screening programs of natural product-based drug discovery. The marine environment in particular offers novel and chemically rich actinomycetes species [2] . Among actinomycetes, genus Streptomyces continues to be a rich source of novel bioactive compounds and many antibiotics remain unexplored. Most searches to discover novel compounds usually end up unfruitful as previously reported species and compounds repetitively get identifed. In spite of taxonomic relatedness of the strains, nutritional requirements for growth and *Address for correspondence E-mail: mobeen.pharma@gmail.com This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms Accepted 25 August 2018 Revised 26 February 2018 Received 12 April 2017 Indian J Pharm Sci 2018;80(5):911-920 antibiotic production were strain-dependent [3] rather than species-specifc, implying the possibility of different strains of the same species producing same compounds less frequently. Thus novelty of compounds among different strains is theoretically more possible. Secondary metabolomes unexplored gene clusters of ubiquitous species of actinomycetes can drive the discovery of novel lead molecules [2] . However, only a small fraction of secondary metabolomes have been investigated till date, owing to the scarcity of effcient procedures to connect genes to molecules [4] , as many of the gene clusters encoded by Streptomycetes are not expressed under normal laboratory growth conditions. Minor changes in medium components Bioprocess Development Employing Design of Experiments for Antibiotic Production from Streptomyces parvulus Strain Sankarensis-A10 Sk. MOBEEN* AND G. GIRIJA SANKAR Pharmaceutical Biotechnology Division, A. U. College of Pharmaceutical Sciences, Andhra University, Visakhapatnam-530 003, India Mobeen et al.: Bioprocess development employing Design of Experiments Optimization of antibiotic production medium and fermentation conditions of Streptomyces parvulus strain sankarensis-A10 was studied using classical and statistical methods. After selection of the basal production medium, the effect of sea water and incubation time on antibiotic production was investigated by classical method. In the frst step of optimization, factors that signifcantly affect antibiotic production such as starch, K 2 HPO 4 , FeSO 4 .7H 2 O, KNO 3 and pH were selected based on Plackett-Burman design. In the second step, three signifcant factors, starch, KNO 3 , pH, with a positive effect were optimized with a 33 factorial Box- Behnken design and analysed using response surface analysis. The optimal values for maximum antibiotic production were as follows, starch- 20 g/l, pH- 8.0 and KNO 3 - 3 g/l. Under optimal conditions, the antibacterial activity was found to be 620 U/ml and 616.66 U/ml against Staphylococcus aureus and Escherichia coli, respectively, which indicated that the activity was 1.4 folds higher in contrast to antibacterial activity prior to optimization. TLC-based partial purifcation of crude extract and bioassay of the fractions revealed the presence of four active compounds with R f values of 0.275, 0.2, 0.125 and 0.062. These could probably be novel bioactive compound(s) in the crude extract, which could prove to be a novel source of antibiotics. Key words: Antimicrobial activity, antibiotic production medium, Plackett-Burman design (PBD), response surface analysis, thin-layer chromatography