Recent developments in the biosynthesis of nanomaterials have demonstrated the important role of biological systems and microorganisms in nanoscience and nanotechnology. These organisms show a unique potential in environmentally friendly production and accumulation of nanoparticles with different shapes and sizes. Therefore, researchers in the field of nanoparticle synthesis are focusing their attention to biological systems. In order to obtain different applied chemical compositions, controlled monodispersity, desired morphologies (e.g., amorphous, spherical, needles, crystalline, triangular, and hexagonal), and interested particle size, they have investigated the biological mechanism and enzymatic process of nanoparticle production. In this review, most of these organisms used in nanoparticle synthesis are shown.

Production of nanoparticles using organisms

Extracellular biosynthesis of silver nanoparticle using Azadirachta indica leaf extract and its anti-microbial activity

The present study was carried out to synthesize silver nanoparticles (AgNPs) using extracts of wild edible mushroom, Pleurotus giganteus, and to characterize the synthesized AgNPs and also to evaluate the synthesized AgNPs for antimicrobial and α-amylase inhibitory activity. Green synthesized AgNPs were characterized by UV–Vis spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, Atomic force microscopy (AFM), Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), selected area electron diffraction (SAED), Energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). Antibacterial activity of AgNPs was studied by disc diffusion method along with minimum inhibitory concentration (MIC) and α-amylase inhibition assay of AgNPs were also studied. UV–Vis spectra of reaction mixture of AgNPs exhibited surface plasmon resonance peak around at 420 nm. FTIR study revealed that mainly carboxyl, hydroxyl, and amine functional groups were present in a mushroom extract which mainly reduced Ag+ to Ag0. AFM, TEM, SEM, SAED, and XRD pattern analysis supported that synthesized AgNPs were mostly spherical shaped within average size 2–20 nm and crystalline in nature. Biosynthesized AgNPs showed more antibacterial potentiality against Gram (–) bacteria. MIC of green synthesized AgNPs were found against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus as 12, 10, 14, and 15 μg/ml, respectively. α-Amylase inhibition assay of green synthesized AgNPs revealed that percent inhibition of α-amylase decreased with increasing concentration of green synthesized AgNPs. Wild edible mushroom P. giganteus can be used as a source of reducing and capping agents of spherical metallic silver nanoparticles which offers potential medicinal properties.

Green Synthesis of Silver Nanoparticles Using Mushroom Extract of Pleurotus giganteus: Characterization, Antimicrobial, and α-Amylase Inhibitory Activity

The present investigation was conducted to synthesize and characterize silver nanoparticles using wild edible mushroom extract of Lentinus tuber-regium. The current investigation also aims to determine antimicrobial and α-amylase inhibitory activity of biosynthesized silver nanoparticles (AgNPs). UV–Visible spectrophotometer study indicated that the surface plasmon resonance peak of reaction of AgNPs was around at 433 nm which confirmed the formation of AgNPs. Fourier-transform infrared spectroscopy analysis confirms that carboxyl functional groups in mushroom extract are mainly responsible in reduction of Ag+ ions to Ag0 nanoparticles. Atomic force microscopy, transmission electron microscopy and scanning electron microscopy analysis revealed that synthesized AgNPs were spherical and have an average size within 5 to 35 nm. Selected area electron diffraction and X-ray diffraction pattern displayed that synthesized AgNPs were crystalline in nature. Energy-dispersive X-ray spectroscopy study showed 10.50% of silver metal in weight in the sample. Biosynthesized AgNPs showed more antibacterial activity in Gram (−) bacteria than Gram (+). Minimum inhibitory concentration values of the biosynthesized AgNPs against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus and Bacillus subtilis were found to be 9, 12, 14 and 13 µg/ml, respectively. Inhibition of α-amylase activity increased with increasing concentration of biosynthesized AgNPs. This work substantially indicates that mushroom is efficient in biosynthesis of silver nanoparticles having potential antimicrobial and α-amylase inhibitory activity.

Characterization, Antimicrobial and α-Amylase Inhibitory Activity of Silver Nanoparticles Synthesized by using Mushroom Extract of Lentinus tuber - regium

The present invention provides a new inhibitor for Bacillus cereus which has been designated officially as a pathogen of food poisoning, which comprises a protamine or its salt as an essential component.

Multiplication inhibitor for Bacillus cereus

Purification of phospholipase C from Bac. cereus by chromatography on aminoalkylpolysaccharide adsorbents is described. The dependence of the degree of enzyme purification on the amount of ligant and effect of pH and buffer systems on the adsorption-desorption of phospholipase have been studied. At a pH below 9.0 phospholipase C is not retained by the adsorbents and is purified 4-5-fold and up to 23-fold, when aminoalkyl-Sepharose and hexamethylenediamine Sephadex are used respectively. With an increase in the pH value up to 10.0, the enzyme is bound by the adsorbent and is eluted with a 40-90% yield of activity and 7-10-fold purification. The resulting phospholipase C is highly purified and electrophoretically homogeneous. A mechanism of the enzyme-adsorbent interaction is discussed.

Purification of phospholipase C from Bacillus cereus by chromatography on aminoalkylpolysaccharide adsorbents

Phospholipase activity of 10 strains of Bacillus cereus was studied. The most active strain of Bac. cereus--phospholipase producer was selected. A cultivation mixture of Bac. cereus optimal for the phospholipase synthesis was found to include peptone, yeast extract, glucose, NaCl and Na2HPO4. Proper conditions for the synthesis of phospholipase in flasks, 20 l and 250 l fermenters were tested. The maximum increase of the phospholipase activity occurred by the 5-9th hour of microbial growth at pH 6.0-8.0. Further cultivation, foaming, strong aeration, pH increase (over 8.0) reduced the accumulated activity. By fractionation with (NH4)2SO4, ethanol precipitation, protamine sulphate treatment with subsequent Sephadex G-100 gel filtration phospholipase (EC 3.1.4.3) was purified 300-fold from the culture liquid of Bac. cereus str. 504. The preparation was examined electrophoretically in 7% polyacrylamide gel at alkaline pH. The effect of metal salts and EDTA on phospholipase activity was studied. Thermostability, substrate specificity and pH optimum of purified phospholipase were investigated.

Phospholipase of Bacillus cereus

The nutrient medium to provide rapid growth of microbial cells of Bacillus cereus str. 504, and biosynthesis of extracellular phospholipase C(EC 3.1.4.3) was selected. The nutrient medium contained acidic casein hydrolyzate, yeast extract or enzymatic hydrolyzate of fodder yeast, glucose, NaCl, NaHCO3, and Na2HPO4. The activity of secreted phospholipase C reached maximum at pH 6.3--6.6.

Gerasimene Gb

Papers

Purification of phospholipase C from Bacillus cereus by chromatography on aminoalkylpolysaccharide adsorbents

Phospholipase of Bacillus cereus

Biosynthesis of extracellular phospholipase C (lecithinase) from Bacillus cereus depending on the nutrient medium composition and pH