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The green synthesis of metal nanoparticles has received substantial attention due to their applications in various domains. The aim of the study was to obtain silver nanoparticles (AgNPs) by green synthesis with filamentous fungi, such as Cladosporium cladosporoides, Penicillium chrysogenum, and Purpureocillium lilacinum. Fungal species were grown on nutrient media and aqueous mycelium extracts were used to reduce Ag+ to Ag (0). The silver nanoparticles were analyzed by various techniques, such as UV-Visible spectroscopy (UV-Vis), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), dynamic light scattering (DLS), and Zeta potential. The formation of silver nanoparticles was confirmed by UV-Vis spectroscopy and the color change of the mixture containing metal precursor and aqueous mycelium extract. FTIR displayed different functional groups as capping and reducing agents for the biosynthesis of AgNPs. SEM and TEM provided information on the particles' morphology. DLS diagrams indicated mean particle diameters in the 124–168 nm region. All biosynthesized AgNPs had negative zeta values, which is a sign of good stability. Silver nanoparticles were evaluated for antimicrobial activity, and the most active were those synthesized with metabolites from Cladosporium, leading to 93.75% inhibition of Staphylococcus aureus, 67.20% of Escherichia coli, and 69.56% of Candida albicans. With the highest microbial inhibition percentage and a very good Poly Dispersion Index (Pd I), Cladosporium cladosporoides was selected as an environmentally friendly source of silver nanoparticles that could be used as a potential antimicrobial agent. [ABSTRACT FROM AUTHOR]

Several strategies promote phyllosphere colonization by soil-born Trichoderma plant-beneficial strains. One of these strategies is foliar spraying with suspensions containing large amounts of chlamydospores—spores with thick cell wall structures that make them highly resistant to harsh environmental conditions. Trichoderma biomass was produced by cultivation on a cornmeal medium and compared with the biomass produced on potato dextrose broth by microscopic and thermogravimetric analyses. The analyses revealed increased chlamydospore content and thermostability in the fungal biomass produced on the corn meal medium. The Trichoderma suspension rich in chlamydospores was sprayed on bitter gourd (Momordica charantia) leaves at two inoculant concentrations, 106 and 108 ufc/mL. The effect of these treatments on the plant physiological parameters, leaf photosynthetic pigments, polyphenol and flavonoid contents, antioxidant activities of the leaves and fruits, and yield was compared to the control (plants sprayed with water) and to the experimental treatment involving spraying with 108 ufc/mL of propagules produced in potato dextrose broth. The effect of chlamydospore-rich suspensions on plant physiological parameters was more pronounced and long-lasting compared with the other treatments. The treatment with chlamydospore-rich suspension enhanced the accumulation of polyphenols and flavonoids in the leaves (by 17% and 50%, respectively) and fruits (by 18% and 31%, respectively) and increased the antioxidant activity. The Trichoderma treatment increased the yield by +25.33–53.07%. The application of the foliar treatment with Trichoderma suspensions did not modify the cytocompatibility of the extracts from the fruits determined on the L929 cells. [ABSTRACT FROM AUTHOR]

Contamination of soil with heavy metals has become a matter of global importance due to its impact on agriculture, environmental integrity, and therefore human health and safety. Several microbial strains isolated from soil contaminated by long-term chemical and petrochemical activities were found to manifest various levels of tolerance to Cr, Pb, and Zn, out of which Bacillus marisflavi and Trichoderma longibrachiatum exhibited above-moderate tolerance. The concentrations of target heavy metals before and after bioremediation were determined using electrochemical screen-printed electrodes (SPE) modified with different nanomaterials. The morpho-structural SEM/EDX analyses confirmed the presence of metal ions on the surface of the cell, with metal uptake being mediated by biosorption with hydroxyl, carboxyl, and amino groups as per FTIR observations. T. longibrachiatum was observed to pose a higher bioremediation potential compared to B. marisflavi, removing 87% of Cr and 67% of Zn, respectively. Conversely, B. marisflavi removed 86% of Pb from the solution, compared to 48% by T. longibrachiatum. Therefore, the fungal strain T. longibrachiatum could represent a viable option for Cr and Zn bioremediation strategies, whereas the bacterial strain B. marisflavi may be used in Pb bioremediation applications. [ABSTRACT FROM AUTHOR]

In the textile, medical, and food industries, many of the applications have targeted the use of textile fabrics with antimicrobial properties. Obtaining eco-friendly coatings is of wide interest, especially for applications related to wound dressing or to food packaging. In order to obtain coatings with antimicrobial properties through environmentally friendly methods, a series of experiments were carried out on the use of natural polymers loaded with silver nanoparticles. In this study, coatings with antimicrobial properties were obtained by depositing natural composites based on rice flour, carob flour, or alginate on cotton fabrics. These antimicrobial coatings were multicomponent systems, in which the host matrix was generated via hydration of natural polymers. The nanocomposite obtained from the phytosynthesis of silver particles in ginger extract was embedded in hydrogel matrices. The multicomponent gels obtained by embedding silver nanoparticles in natural polymer matrices were deposited on cotton fabric and were studied in relation to nanoparticles and the type of host matrix, and the antimicrobial activity was evaluated. Fabrics coated with such systems provide a hydrophilic surface with antimicrobial properties and can therefore be used in various areas where textiles provide antibacterial protection. [ABSTRACT FROM AUTHOR]

"Green chemistry" is a simple and easily reproductible method that provides nanoparticles characterized by better stability and good dispersion in an aqueous solution. Nanoparticles can be synthesized by algae, bacteria, fungi, and plant extracts. Ganoderma lucidum is a commonly used medicinal mushroom with distinctive biological properties, such as antibacterial, antifungal, antioxidant, anti-inflammatory, anticancer, etc. In this study, aqueous mycelial extracts of Ganoderma lucidum were used to reduce AgNO3 to form silver nanoparticles (AgNPs). The biosynthesized nanoparticles were characterized by UV-visible spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) analysis. The maximum UV absorption was obtained at 420 nm, which represents the specific surface plasmon resonance band for biosynthesized silver nanoparticles. SEM images showed particles as predominantly spherical, while FTIR spectroscopic studies illustrated the presence of functional groups that can support the reducing of ion Ag+ to Ag(0). XRD peaks ratified the presence of AgNPs. The antimicrobial effectiveness of synthesized nanoparticles was tested against Gram-positive and Gram-negative bacterial and yeasts strains. The silver nanoparticles were effective against pathogens, inhibiting their proliferation, and thus reducing the risk to the environment and to public health. [ABSTRACT FROM AUTHOR]

In this study curcumin was immobilized in a silica matrix to overcome its poor aqueous solubility and rapid degradation profile. Two kinds of sol–gel powders based on colloidal silica were synthesized and characterized, one prepared with an ethanolic solution of curcumin and the other using cethyltrimethylammonium bromide (CTAB) to solubilize the dye. The successful integration of curcumin in the matrix as well as the interaction with the components of the composite powders was validated by different analysis methods (DSC, FTIR). The samples morphology was evaluated by SEM. UV–Vis and fluorescence studies showed that curcumin was stable, in its enol configuration in both matrices. The sensitivity to ammonia was proved by exposing the powders to NH3 vapors in a sealed vessel. Color changes were measured with a colorimeter. UV–Vis spectra showed that the enol form of the dye in EtOH/CTAB based SiO2 matrices was energetically stable under NH3 atmosphere, even after being kept a few days at low temperature. A fluorescence quenching of both samples was noticed due to interaction curcumin-ammonia. Both samples have antimicrobial properties, the CTAB containing one being more efficient. The EtOH/CTAB based SiO2 powders may represent a novel signaling and antimicrobial system, useful for food or pharmaceutical applications. [ABSTRACT FROM AUTHOR]

We describe the optimization of cultivation medium composition for biosynthesis of Trichoderma asperellum T36 biomass. This Trichoderma strain is a multifaceted one, being antagonist against major plant pathogens, stimulating vegetables growth, enhancing bioactive accumulation into nutraceutical crops and promoting development on early stages of the plants cultivated into high residues system. To improve the eco-efficiency of T36 based bioproducts production, a maximum conversion of cultivation medium components into fungal biostimulant biomass is required. We optimize the cultivation medium through a designed experiment, based on surface response methodology, wherein several components of cultivation medium were modified in the same time. The studied components were: glucose (carbon source), ammonium sulphate (inorganic nitrogen and sulphur source), soymeal and yeast extract (complex, organic nitrogen source and growth factors source), potassium mono- and di-hydrogen-phosphates (as phosphorus source and buffering ingredients). The optimal composition of cultivation medium, resulted after experimental results analysis, is: 34.2 g. l-1 glucose, 0.37 g. l-1 ammonium sulphate, 0.8 g. l-1 yeast extract, 2.7 g. l-1 soymeal, 1.2 g. l-1 K2HPO4, 1.7 g. l-1 KH2PO4. We compared the tolerance to dry-flowable formulation of T. asperellum T36 biomass produced on optimized liquid media and on liquid Weidling media. The biomass produced on optimized media has a better tolerance to dry-flowable formulation than biomass produced on Weidling media. Also, the preservation of biological activities, specific to T36 strain, is better on dry-flowable formulation produced with biomass resulted from optimized medium than that with biomass resulted from liquid Weidling medium. Higher tolerance to dry-flowable formulation and better survival rate, of formulated T36 propagules, suggest that optimized medium promote formation of more resilient fungal resting structures. A techno-economic analysis was performed for the optimized cultivation medium. [ABSTRACT FROM AUTHOR]

The genus Phytophthora causes great damages to agricultural production, especially to potatoes and tomatoes cultures. To face these losses, it is of interest to reduce or inhibit the activity of this aggressive pathogen. Some species of Trichoderma have great potential for the biological control of several plant pathogens, including diseases caused by Phytophthora parasitica, Rhizoctonia solani, Pythium ultimum, Fusarium oxysporum, Sclerotinia sclerotiorum etc. The purpose of this study was to assess the biocontrol efficacy of three Trichoderma strains (T. asperellum T36, T. asperellum T50, T. harzianum T78) against Phytophthora parasitica. In vitro tests were carried out using dual culture technique. In vivo tests were carried out with pepper seedlings (Capsicum annuum cv. Lamuyo) and conidial standard suspension of Trichoderma isolates as biocontrol agents. Of the three Trichoderma isolates tested for their effectiveness against mycelial growth of pathogen, T. asperellum T36 (81.2%) exhibited maximum inhibition of P. parasitica, compared with the control, followed by T. asperellum T50 (79.6%) and T. harzianum T78 (77.7%). Likewise for the in vivo test, the inoculation of the Trichoderma biocontrol agent showed that the percentage of dead plants seedlings was significant reduced. T. asperellum T36 is a useful biological alternative to pesticides for the control of P. parasitica in pepper seedlings. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the influence of culture conditions on growth of keratinophilic fungal strain of Chrysosporium sp. in the presence or absence of keratin substrate. The effect of pH, temperature, carbon and nitrogen sources on fungal growth and sporulation was evaluated. The pH values ranged from 4 to 9.5 and the incubation temperature ranged from 20°C to 35°C. Glucose, fructose, maltose, sucrose, starch and cellulose were used as carbon sources. As nitrogen source, yeast extract, ammonium salts, urea and vitamin B12 were tested. All tests were also performed with basal mineral culture medium supplemented with keratin powder from chicken feathers. The feathers were cleaned with ethylic alcohol, washed with distilled water, dried at 60°C and finally grounded several times with a Retsch ball mill until a fine powder was obtained. The influence of the culture conditions on growth was assessed by measuring the diameter of the colonies grown on the solid medium after 5 and 10 days of incubation. The colony sporulation degree was appreciated macroscopically and microscopically. The presence of keratin in the culture media stimulated distinctly the fungal growth as compared to the culture media without keratin. Alkaline pH and temperatures between 27 and 30°C are optimal for its growth. Certain C and N sources can stimulate the fungal growth, but this seems to be influenced by the incubation time. [ABSTRACT FROM AUTHOR]

Keratinophylic fungi are present in the environment with a variable distribution, being influenced by human and animal presence and playing an important role in the biodegradation of keratinized substrates (skin, hair shaft, nails, claws, horns, wool and feathers). These fungi are geophilic, zoophilic and anthropofilic. Keratinophylic fungi have the ability to degrade keratinized materials, using the keratin as the sole source of carbon and nitrogen. This behaviour is based on the activity of keratinases, enzymes belonging to the group of proteases that can specifically degrade keratin. The aim of the present study was to evaluate the biodegradative ability of some keratinophylic fungal strains, clinical and geophilic isolates. The tested keratinized substrates were represented by animal hair strands. The rate of keratinized substrates biodegradation was expressed as weight loss over three weeks of incubation in minimal liquid medium in an orbital incubator. The morphological changes of hair samples were observed by light microscopy and scanning electron microscopy (SEM). [ABSTRACT FROM AUTHOR]

Research in the field of natural dyes has constantly focused on methods of conditioning curcumin and diversifying their fields of use. In this study, hybrid materials were obtained from modified silica structures, as host matrices, in which curcumin dyes were embedded. The influence of the silica network structure on the optical properties and the antimicrobial activity of the hybrid materials was monitored. By modifying the ratio between phenyltriethoxysilane:diphenyldimethoxysilane (PTES:DPDMES), it was possible to evaluate the influence the organosilane network modifiers had on the morphostructural characteristics of nanocomposites. The nanosols were obtained by the sol–gel method, in acid catalysis. The nanocomposites obtained were deposited as films on a glass support and showed a transmittance value (T measured at 550 nm) of around 90% and reflectance of about 11%, comparable to the properties of the uncovered support. For the coatings deposited on PET (polyethylene terephthalate) films, these properties remained at average values of T550 = 85% and R550 = 11% without significantly modifying the optical properties of the support. The sequestration of the dye in silica networks reduced the antimicrobial activity of the nanocomposites obtained, by comparison to native dyes. Tests performed on Candida albicans fungi showed good results for the two curcumin derivatives embedded in silica networks (11–18 mm) by using the spot inoculation method; in comparison, the alcoholic dye solution has a spot diameter of 20–23 mm. In addition, hybrids with the CA derivative were the most effective (halo diameter of 17–18 mm) in inhibiting the growth of Gram-positive bacteria, compared to the curcumin derivative in alcoholic solution (halo diameter of 21 mm). The results of the study showed that the presence of 20–40% by weight DPDMES in the composition of nanosols is the optimal range for obtaining hybrid films that host curcumin derivatives, with potential uses in the field of optical films or bioactive coatings. [ABSTRACT FROM AUTHOR]