Production of silver nanoparticles from the aerobic and anaerobic cultures supernatants of Pseudomonas aeruginosa

Abstract

This study was designed to produce silver nanoparticles from the supernatant of Pseudomonas aeruginosa cultures propagated under aerobic and anaerobic conditions. Silver nitrate solution at concentration 100 mM was added to the supernatants, then thermal treatment at 80 ºC for 4 h. The heated supernatants  were then burned at 600 ºC for 3h. Silver nanoparticles products were characterized using qualitative and quantitative tests. Morphological observation of the supernatants color change was made after adding silver nitrate and heating treatment.. The color of supernatant was changed into dark brown and light brown for each aerobic and anaerobic cultures supernatants, respectively. Quantitative tests included the analytical measurements for determination the ƛ_max for aerobic and anaerobic supernatants after heating treatment in range of 300-500 nm to record the silver nanoparticles production and two peaks were obtained at 390 and 420nm, respectively. FTIR analysis schemes of the supernatants after thermal treatment at 80 ºC showed differences in composition of active compounds since more groups in the supernatant of aerobic supernatant were noted. No specific active groups were observed after burning the samples. Scanning electron microscopy (SEM) images of burned supernatants were conducted and revealed the presence of small nanoparticles for aerobic treatment in comparison with anaerobes. The results of atomic force microscopy(AFM) showed that aerobic the treatment was produced a silver nanoparticles of approximate diameters of 20-50nm compared with anaerobic  treatment (50-100nm).