Eradication of water borne pathogens using novel green nano Ag-biocomposite of Citrus Limetta peels

Abstract

Water borne pathogens pose a great threat to the health-care system and their mitigation poses a formidable challenge prompting researchers to find innovative and effective methods for pathogen control. Large scale implementation technologies for wastewater treatment need to be economical and facile. We have utilized industrial waste from citrus fruits to develop green nano-biocomposite materials. Green nano-biosynthesis methods are known to be cost effective, non-toxic and environment friendly that have attracted attention recently. The present study utilized citrus industry waste raw Citrus limetta peels as bio-reducing and stabilizing agents directly, instead of extract for the synthesis of silver nanoparticles. Characterization of the synthesized silver nanoparticles by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) confirmed the impregnation of nano-silver with size range of 5−10 nm inside Citrus limetta peels that has been designated as CL-AgNPs. Antibacterial activity of CL-AgNPs was evaluated against the most prevalent waterborne pathogens for treating waste water from domestic and municipalities. The antibacterial activity was linked to nano-silver’s membrane permeabilization mode using LIVE/DEAD staining technique. The antibacterial potential of CL-AgNPs was also tested in batch and continuous experiments separately, which showed attenuation in bacterial load within 5 min exposure of CL-AgNPs as demonstrated by growth kinetics study. Furthermore, CL-AgNPs was found to be safe and did not exhibit cytotoxiceffects on human red blood cells (RBCs) up to 10X MIC. These findings infer that CL-AgNPs could be employed for cost-effective treatment of contaminated waste water after process optimization.