Isolation Characterization and Extraction of Secondary Metabolites showing Antimicrobial Activity against Nosocomial Infections from Mesophilic soil Of Rajasthan

Abstract

Rajasthan has high temperature almost 8 to 9 months in a year and thus was selected as the most suitable site for collection of soil-inhabiting microbiota, adapted to mesophilic temperature. Four different locations were selected, viz. Mansarovar, SMS Hospital, Durgapura Railway station and Jawahar Circle. Through the primary stage of screening methods of microbiology, twenty nine colonies were selected from the four soil samples. Further, secondary screening narrowed the result to nine isolates which were processed to test the respective biological activity against the common pathogens prevailing in India as well as other parts of the world. The methods used were cross streak plating, agar well diffusion method and disc diffusion method. newline newline For the extraction of secondary metabolites from the microbial cells, the count was first increased by up-scaling the isolates and providing them stress conditions to induce the releases of secondary metabolites. This was followed by separation of secondary metabolites from the broth with the help of the property of the compounds to solubilize in particular solvent system. Three solvent systems were employed in this protocol of liquid liquid extraction, namely, benzene, chloroform and ethyl acetate. The metabolites were purified and subjected to GC-MS analysis for identification. newline newline The GC-MS results revealed the presence of 39 different compounds which have been reported to possess anti-microbial activities, along with other biological characteristics. Preparative TLC with the standards validated the GC-MS results. The identification of the nine isolates was performed by 16s rRNA sequencing protocol. The isolates identified were Bacillus licheniformis, Providencia rettgeri, Bacillus subtilis subsp. In a quosorum, Brevibacillus borstelensis, Bacillus cereus, Bacillus thuringiensis, and Stenotrophomonas acidaminiphila. Every stage of the present research work was validated by performing anti-microbial sensitivity testing against the common pathogens, to confirm the success of the ongoing study. This study could out to be useful in the field of pharmaceutical science, as load on medicinal plants can be reduced by replacing them with the screened isolates, for the production of some of the essential bioactive components. newline newline