Citrate-silver nanoparticles and their impact on some environmental beneficial fungi

Abstract

Colloidal suspensions of silver nanoparticles (AgNPs) with surface modified by capping with citrate ions were synthesized by chemical reduction method. Transmission and Scanning Electron Microscopy as well as darkfield Optical Microscopy provided information on the nanoparticle morphology, with fine symmetrical grains and log-normal fitted size distribution. Small Angle X-ray Scattering method allowed theoretical confirmation of colloidal silver nanoparticle fine granularity, based on measurements in the native fluid sample. UV–Vis spectrophotometry allowed studying the Localized Surface Plasmon Resonance band versus the stability of the citrate-AgNP sample after storage and after UV-C exposure. The colloidal AgNP impact on Phanerochaete chrysosporium environmental microorganisms was studied by specific biochemical investigations. Silver released from the colloidal suspension of AgNPs was supposed to induce changes in some antioxidant enzymes and in some enzymes of Krebs’ cycle. Catalase activity was moderately changed (an increase with over 50%) as well as superoxide dismutase activity, while the diminution of the activities of four dehydrogenases synthesized in the fungus mycelium was emphasized also: a decrease with about 60% for malate dehydrogenase, with over 50% for isocitrate dehydrogenase and succinate dehydrogenase and with about 40% for alpha-ketoglutarate dehydrogenase. These findings suggested the nano-toxicological issues of citrate-AgNPs impact on the environmental beneficial microorganisms.

Photochemical Synthesis of Gold and Silver Nanoparticles—A Review

“…The two-step process promotes the efficient synthesis of Ag NPs since the reduction of silver ions is totally completed during the first step. As a result, the pH slightly increased from 5 to 6 while the SPR band maximum blue-shifted from 425 nm to 418 nm, suggesting the formation of smaller Ag NPs; this corroborates studies that reported the influence of increasing pH on the narrowing and position of the Ag NP SPR band [ 129 , 130 ].…”

“…Some studies suggest that the Ag NP size tends to decrease in alkaline media due to the rapid nucleation, while acidic media results in larger Ag NPs since the reaction rate is slower [ 127 , 128 ]. Furthermore, the pH affects the absorption of light and the position of the localized SPR (LSPR) band [ 126 , 129 ]. Babusca et al synthesized Ag NPs via a two-step process: the aqueous mixture of AgNO 3 and trisodium citrate was heated then irradiated using a UV-C lamp (30 W) for 45 min [ 126 ].…”

Metal Nanoparticle Synthesis Using Fruit Extracts as Reducing Agents and Comparative Studies with a Chemical Reducing Agent

“…Just before the boiling point, 5 ml of 1% trisodium citrate was added drop by drop to this solution. Vigorous mixing was carried out during the process to increase the interaction of the reagents, the reaction mixture was maintained at over 60 °C, until its color changed to grey 10 .…”

Nitrapyrin Addition Mitigated CO2 Emission from a Calcareous Soil Was Closely Associated with Its Effect on Decreasing Cellulolytic Fungal Community Diversity

“…Soil cellulolytic fungal community was found to be easily influenced by exogenous additives. 25,26 For example, Pampulha and Oliveira 27 observed that combined application of bromoxynil and prosulfuron significantly decreased the abundance of the cellulolytic fungal community. Similarly, the addition of the medicinal herb Isatis indigotica strongly inhibited the growth of cellulolytic fungal groups such as Penicillium and Fusarium.…”