ABSTRACT
A total of 75 isolates belonging to five different species of Trichoderma viz., T. asperellum, T. harzianum, T. longibrachiatum, T. pseudokoningii and T. virens were screened for the production of silver nanoparticles. Although all the isolates produced nanoparticles, T. virens VN-11 could produce maximum nanoparticles as evident from the UV-Vis study. The highest Plasmon band was observed at 420 nm at every 24 h that attained maximum intensity at 120 h (0.543). The high resolution transmission electron microscopy (HRTEM) further provided the morphology of the nanoparticles. These nanoparticles were found single or aggregated with round and uniform in shape and 8-60 nm in size. The nitrate reductase activity of VN-11 was found to be 150 nmol/h/mL which confirmed the production of silver nanoparticles through reduction of Ag+ to Ag0.
Subject(s)
Metal Nanoparticles/chemistry , Metal Nanoparticles/ultrastructure , Microscopy, Electron, Transmission , Nanotechnology , Nitrate Reductase/metabolism , Particle Size , Silver/chemistry , Trichoderma/classification , Trichoderma/metabolismABSTRACT
Biosynthesis of gold nanoparticles has emerged as an important area in nanotechnology and biotechnology due to growing need to develop environmentally benign technologies. Generally, nanoparticles are prepared by a variety of chemical methods which are not environmentally friendly. In the present study, we report a rapid and convenient method to reductively prepare gold nanoparticles from auric chloride using aqueous extract of Mirabilis jalapa flowers. The flower extract acts as a reducing agent and encapsulating cage for the gold nanoparticles. The production of gold nanoparticles has been done by the controlled reduction of the Au3+ ion to Au0. The formation of gold nanoparticles has been established by FT-IR and UV-Vis spectroscopy, as well as by TEM, XRD, EDAX and AFM. The study suggests that M. jalapa flowers can be a cheap source as a reductant for the production of gold nanoparticles.