Preparation of the silver nanoparticles
The fungal strain P. purpurogenum NPMF (MTCC
7356) was obtained from the culture collection center
of Biominerals Department of IMMT, Bhubaneswar.
All chemicals used were of analytical grade. P.
purpurogenum was grown in cornmeal medium
(HIMEDIA) which was composed of 20 g/L of corn
meal, 10 g/L of peptic digest of animal tissue, 4 g/L
of yeast extract, and 10 g/L of dextrose. The pH of
the media was adjusted to 6.8 ± 0.2. For production
of biomass, sterile media was inoculated with fungal
spores aseptically and incubated at 35 C under
shaking condition. After growth of fungus, biomass
was separated and re-suspended in distilled water.
Then after incubation with water the culture filtrate
(extra-cellular enzymes) so generated was added with
AgNO3. The concentration of AgNO3 was maintained
at 1 mM level throughout all the experiments
barring few experiments. A control experiment of
fungal supernatant without AgNO3 was conducted
under similar conditions.