Silver nanoparticles biosynthesized using microorganisms and their incorporation into fruit packing paper

JORGE G. FERNÁNDEZ; MARTÍN A. FERNÁNDEZ BALDO; ELOY SALINAS; JULIO RABA; MARÍA I. SANZ

Rosario

Congreso; IX Congreso Argentino de Microbiología General; 2013

Sociedad Argentina de Microbiología General

Nanobiotechnology is a field that is burgeoning day by day, making an impact in all spheres of human life. Biological methods of synthesis have paved way for the ?greener synthesis? of nanoparticles and these have proven to be better methods due to slower kinetics, they offer better manipulation and control over crystal growth and their stabilization. This has motivated an upsurge in research on their applicability in many areas including the biomedical, agricultural, optical, and electronic fields. In the present work the objective was to study the applicability of Ag NPs biosynthesized for their incorporation into fruit packing paper. To achieve extracellular biosynthesis of silver nanoparticles, a silver nitrate solution was added to the filtrate of a culture of the fungus Aspergillus niger and the yeasts Cryptococcus laurentii and Rhodotorula glutinis. AgNPs were characterized by spectroscopic analyses of surface plasmon resonance (SPR) and transmission electron microscopy. The presence of Ag NPs was confirmed by the SPR band around 440 nm for the three microorganisms studied. The transmission electron microscopy showed the size of the silver nanoparticles from A. niger is of 40±20 nm and around of 35±10 nm for the two yeasts.The antifungal activity of Ag NPs was tested against strains of Botrytis cinerea and Penicilium expansum. 200 μL of fungus spores (2x106 spores mL-1 ) of each strain studied were aseptically placed into potato dextrose agar plates. Also, fruit packing paper discs (3 cm diameter) were impregnated with AgNPs. The disks were placed in contact with 60 μL of Ag NP and were allowed to air dry for 24 hs. The plates were incubated at 28±4ºC for 7 days. After incubation the zones of inhibition were measured. Packing paper discs were impregnated with Ag NPs chemical synthesis as control. The paper discs impregnated with AgNPs biosynthesized showed a higher antifungal activity than the impregnated with AgNPs of chemical synthesis. The paper discs impregnated with AgNPs from R. glutinis showed the largest zone of inhibition, followed by the C. laurentti and A. niger against two fungal pathogens tested.