Statistical Optimization of Parameters for Enhanced Bioactive Metabolites Produced by Streptomyces hygroscopicus AVS7

The modern technology focuses on developing a novel statistical approach for highest yield of bioactive microbial metabolites which contain therapeutic properties, eventually leading to a promising strategy for treating various diseases and disorders. In this research, we aimed to develop the optimization process for maximum yield of crude pigmented secondary metabolites (CPSM) from Streptomyces hygroscopicus AVS7 through statistical approaches and determine its antimicrobial activity. The isolate produced maximum of 2.92 g/L on 9th day in starch casein nitrate (SCN) medium, and employing the SCN medium as seed medium, the research has initiated one factor at a time (OFT) for screening the essential physical, physiological and biological parameters. The OFT-screened factors were further determined for their importance through Plackett–Burman (PB) design, and the PB results revealed the significant factors (sesame oil cake, KNO3, glycerol, glucose, casein and urea). The experimentation was carried to Box-Behnken (BB) design–RSM using significant factors for the evaluation of interaction between the factors influencing the highest yield of CPSM, and the model was validated. The maximum CPSM extract was yielded by culturing the S. hygroscopicus AVS7 in the optimized medium, and there was twofold increase in the yield of CPSM extract when compared to seed medium. This statistical approach is a low-cost and economical method to develop maximum CPSM for medicinal and industrial purposes. The produced CPSM was found to contain the antimicrobial properties. Further, the research leads to the in vitro and in vivo assessment of purified bioactive secondary metabolite.