Antibacterial potential of a small peptide from Bacillus sp RPT-0001 and its capping for green synthesis of silver nanoparticles

Infirmity and death from diseases caused by unsafe food are a continual hazard to communal health safety and socio-economic growth throughout the world. Chemical preservatives are associated with health hazards and toxicity issues. In the study reported here, 200 soil isolates from Western Himalayan region in India were screened for potential antibacterial activity against food-borne pathogens. This study led to the isolation of a bacterial strain belonging to the Genus Bacillus and was designated as RPT-0001. The associated antibacterial activity was sensitive to pronase E treatment. Bioassay-guided fractionation using reverse phase high performance liquid chromatography (RP-HPLC) led to isolation of the antibacterial peptide designated as RPT-0001. The molecular weight of RPT-0001 was determined by electro-spray ionization mass spectroscopy (ESI-MS) as 276.9 Da. RPT-0001 was inhibitory to both Gram-negative and Grampositive food-borne bacteria tested. The characteristics of RPT-0001 do not match with that of any other known antibacterial peptides produced by Bacillus sp. or related genera. Purified RPT-0001 was successfully used in synthesis of silver nanoparticles effective against food-borne pathogenic bacteria. The antibacterial peptide and silver nanoparticles synthesized utilizing it as a capping and reducing agent hold promising potential in food preservation, in packaging material and as a therapeutic agent in the treatment of foodborne infections.