AMIT PANDEY, ANKITA SRIVASTAVA, NIHARIKA CHANDRA, DHEERENDRA KUMAR AND SUNIL KUMAR
Abstract
The search for new bioactive compounds from the natural environment has rapidly been gaining momentum with the increase in multi- drug resistant (MDR) pathogens. In the present study, the antimicrobial potential of new bacterial species has been evaluated by initial screening of fourteen soil samples. Primary and secondary screening was performed against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. Four active isolates were selected for further study. Microbial strains were identified on the basis of growth conditions and other biochemical characters. One most active microbial strain was identified using 16S-rRNA sequence homology and designated as Bacillus cereus (C13). Furthermore the optimization of four selected isolates (those having antibacterial activity; C1, C11, C12, C13) was performed. For all four cultures, Glucose and Ammonium chloride were found to be the best sources of carbon and nitrogen respectively. In addition to this pH 7 and 37 oC temperature were found to be best for optimum growth. The different concentration of NaCl was used for salt tolerance. In conclusion, we study the isolation of new strains of bacteria for producing bioactive compounds having antibacterial activities. Also, this study paves the way for further characterization of the secondary metabolites of Bacillus cereus, for their optimum utilization as antibacterial agents against multidrug resistant pathogens.