1. First utilization of magnetically-assisted photocatalytic iron ▫$oxide-TiO_2$▫ nanocomposites for the degradation of the problematic antibiotic ciprofloxacin in an aqueous environmentJosip Radić, Gregor Žerjav, Lucija Jurko, Perica Bošković, Lidija Fras Zemljič, Alenka Vesel, Andraž Mavrič, Martina Gudelj, Olivija Plohl, 2024, original scientific article Abstract: The emergence of antimicrobial resistance due to antibiotics in the environment presents significant public health, economic, and societal risks. This study addresses the need for effective strategies to reduce antibiotic residues, focusing on ciprofloxacin degradation. Magnetic iron oxide nanoparticles (IO NPs), approximately 13 nm in size, were synthesized and functionalized with branched polyethyleneimine (bPEI) to obtain a positive charge. These IO-bPEI NPs were combined with negatively charged titanium dioxide NPs (TiO2@CA) to form magnetically photocatalytic IO-TiO2 nanocomposites. Characterization techniques, including X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), electrokinetic measurements, and a vibrating sample magnetometer (VSM), confirmed the successful formation and properties of the nanocomposites. The nanocomposites exhibited a high specific surface area, reduced mobility of photogenerated charge carriers, and enhanced photocatalytic properties. Testing the photocatalytic potential of IO-TiO2 with ciprofloxacin in water under UV-B light achieved up to 70% degradation in 150 min, with a degradation rate of 0.0063 min−1. The nanocomposite was magnetically removed after photocatalysis and successfully regenerated for reuse. These findings highlight the potential of IO-TiO2 nanocomposites for reducing ciprofloxacin levels in wastewater, helping curb antibiotic resistance.
Keywords: photocatalytic degradation, magnetic iron oxide-TiO2 nanocomposites, hetero-agglomeration, multifunctionality, antibiotic ciprofloxacin, antimicrobial resistance
Published in RUNG: 09.09.2024; Views: 538; Downloads: 6
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2. Antimicrobial efficacy and phytochemical screening of Mushrooms, Lenzites betulinus, and Coriolopsis gallica extracts.Soji Fakoya, Sandra Oloketuyi, 2012, original scientific article Abstract: AIM: The spread of multidrug-resistant strains of bacteria makes it necessary to discover new classes of
antibacterial and compounds that inhibit these resistant mechanisms. Hence, this study was conducted to
evaluate the antimicrobial activities of Lenzites betulinus and Coriolopsis gallica extracts against some
bacterial isolates of medical importance.
METHOD: The organisms are Pseudomonas aeruginosa, Staphylococcus aureus, Proteus vulgaris,
Klebsiella pneumoniae, Escherichia coli. Using agar well diffusion assay, the ethanolic, petroleum ether
and aqueous extract of C. gallica was assayed against the bacterial isolates and the result showed that
Petroleum ether extract of C. gallica and L. betulinus was able to inhibit P. vulgaris with inhibition
zones of 26.0 mm and 20.0 mm respectively.
RESULTS: Ethanolic extract of C. gallica also inhibited P. vulgaris with inhibition zone of 22.0 mm
while aqueous extract and petroleum ether of L. betulinus inhibited P. aeruginosa with inhibition zones
of 20.0 mm and 23.0 mm respectively. E. coli and S. aureus were also inhibited by the aqueous and
ethanolic extract of L. betulinus with zones of inhibition 15.0 mm and 26.0 mm against E. coli while
19.0 mm and 22.0 mm against S. aureus respectively. This study also showed the presence of some
phytochemicals like tannins, phenolics, flavonoids, steroids, and saponin in the mushrooms with
antimicrobial effects against the bacterial isolates used.
CONCLUSION: The active components present in ethanolic, aqueous and petroleum ether extracts of
C. gallica include phenolics, flavonoids, and steroids while phytochemicals obtained from L. betulinus
are phenolics, tannins, flavonoids, and saponin respectively.
Keywords: Coriolopsis gallica, Lenzites betulinus, Antimicrobial, Phytochemicals, Bacterial İsolates
Published in RUNG: 14.01.2021; Views: 2826; Downloads: 0
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3. Applications of Chitosan as Food Packaging MaterialsPatricia Cazón, Manuel Vazquez, 2019, review, book review, critique Abstract: The interest in biopolymers has increased due to the depletion of the fossil fuel reserve and the environmental impact caused by the accumulation of non-biodegradable plastic-based packaging materials. Many biopolymers have been developed from food waste products to reduce this waste and, at the same time, to
obtain new food packaging materials. Chitosan is thus an alternative to synthetic polymers, and a raw material for new materials. To assess the suitability of a material as a food packaging material, it is necessary to study their mechanical and permeability properties. Mechanical properties allow to predict the behaviour of films during transportation, handling and storage of packaged foods. Barrier properties play a key
role in maintaining the food product quality. Properties values depend on the type of chitosan used. Mechanical and barrier properties of pure chitosan films are suitable for food packaging and active packaging. These properties can be modified by combining chitosan with other components such as plasticizers, other polysaccharides, proteins and lipids. These combinations adapt the properties of the final polymer to the needs of
the food to extend its useful life, while maintaining quality properties of the food and the biodegradability of the polymer.
Chitosan displays antimicrobial activity against a wide range of foodborne filamentous fungi, yeast, and gram-negative and gram-positive bacteria. This antimicrobial property and film-forming capacity has made chitosan the reference polymer to develop active packaging with the ability to inhibit the growth of microorganisms and improve food safety. Regarding the optical properties, pure chitosan films in the visible range show high transmittance values, being optically transparent films. This
is an important parameter related to the acceptability of the films by the consumer. In addition, chitosan-based films exhibit remarkable UV absorbance, which allows to protect food from lipid oxidations induced by UV radiation.
Keywords: Film, Mechanical properties, Barrier properties, Antimicrobial, UV
protect, Active food packaging
Published in RUNG: 14.12.2020; Views: 3463; Downloads: 0
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4. Polyphenol, antioxidant and antimicrobial potential of six different white and red wine grape processing leftovers : /Kajetan Trošt, Anja Klančnik, Branka Mozetič Vodopivec, Melita Sternad Lemut, Katja Jug, Peter Raspor, Sonja Smole Možina, 2016, original scientific article Abstract: BACKGROUND
During winemaking, grape polyphenols are only partly extracted, and consequently unexploited. The main aim was to characterise the phenolic content of freeze-dried grape skin and seed (FDSS) extracts obtained from Slovenian and international grape varieties and evaluate their antioxidant, antimicrobial, and anti-adhesive activities.
RESULTS
FDSS of six Vitis vinifera L. grapevine cultivars from Vipava Valley region (Slovenia) underwent extraction and sonification under different conditions. Flavonols were the predominant content of extracts from white ‘Zelen’ and ‘Sauvignon Blanc’ grape varieties, with strong antimicrobial activities against Gram-negative bacteria. ‘Pinot Noir’ FDSS extracted with 50% aqueous ethanol extraction produced a high phenolic content in the final extract, which was further associated with strong antioxidant and antimicrobial activities against all tested bacteria. Bacterial adhesion to stainless steel surfaces with minimal and maximal surface roughness was significantly inhibited (up to 60%) across a wide FDSS concentration range, with lower concentrations also effective with two types of stainless steel surfaces.
CONCLUSION
FDSS extracts from winery by-products show interesting phenolic profiles that include flavonols, catechins, anthocyanins, and hydroxycinnamic acids, with yields influenced by grapevine cultivar and extraction conditions. The antioxidant, antimicrobial and anti-adhesive activities of 50% aqueous ethanol ‘Pinot Noir’ FDSS extract reveals potential applications in food, pharmaceutical and cosmetic industries for these bioactive residues.
Keywords: grape skins and seeds, extraction solvents, phenolic profile, antioxidant activity, antimicrobial activity, anti-adhesion activity to stainless steel
Published in RUNG: 08.08.2016; Views: 6005; Downloads: 0
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