The biological synthesis methods have been emerging as a promising new approach for production of nanoparticles due to their simplicity and non-toxicity. In the present study, spores of Bacillus athrophaeus were used to achieve the objective of developing a green syn- thesis method of silver nanoparticles. Enzyme assay revealed that the spores and their heat inactivated forms (microcapsules) were highly active and their enzymatic contents differed from the vegetative cells. Laccase, glu- cose oxidase, and alkaline phosphatase activities were detected in the dormant forms, but not in the vegetative cells. Although no nanoparticle was produced by active cells of B. athrophaeus, both spores and microcapsules were efficiently capable of reducing the silver ions (Ag?) to elemental silver (Ag0 ) leading to the formation of nanoparticles from silver nitrate (AgNO3). The presence of biologically synthesized silver nanoparticles was deter- mined by obtaining broad spectra with maximum absor- bance at 400 nm in UV–visible spectroscopy. The X-ray diffraction analysis pattern revealed that the nanoscale particles have crystalline nature with various topologies, as confirmed by transmission electron microscopy (TEM). The TEM micrograph showed the nanocrystal structures with dimensions ranging from 5 to 30 nm. Accordingly, the spore mixture could be employed as a factory for detoxi- fication of heavy metals and subsequent production of nanoparticles. This research introduces an environmental friendly and cost effective biotechnological process for the extracellular synthesis of silver nanoparticles using the bacterial spores.
کلید واژگان :Bacillus athrophaeus, Microcapsule, Silver nanoparticles, Spore
ارزش ریالی : 600000 ریال
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