Sahar Zaki, Ayman Kamal, Marwa Elkady, Gadallah Abu-Elreesh and Desouky Abd-El-Haleem
This study aimed to examine the capability of Stenotrophomonas rhizophilastrain 39M isolated from lake water to reduce silver to silver nanoparticles. The production of silver nanoparticles by strain 39M was investigated by UV– visible spectroscopy, X-ray diffraction, transmission electron microscope, scanning electron microscopy and energy dispersive X-ray spectroscopy. The results of UV–visibledemonstrated a peak at 420 nm corresponding to the Plasmon absorbance of silver nanoparticles. SEM micrograph showed a formation of silver nanoparticles in the range of 5–50 nm. XRD-spectrumexhibited 2???Ÿ values corresponding to the silver nanocrystal that produces in hexagonal and cubic crystal configurations with different plane of orientation. In addition, the signals of the silver atoms were observed by EDS-spectrum analysis that confirms the presence of silver nanoparticles. The results demonstrated that after 7 days of incubation culture broth produced the highest yield of silver nanoparticles followed by the cell- free supernatant. The antimicrobial activity of silver nanoparticles against Gram-positive and negative bacteria was assayed. In conclusion, the silver nanoparticles produced in the culture broth of strain M39 could be used successfully as an environmentally friendly disinfector of water and wastewater against pathogenic microorganisms.
