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Antimicrobial Applications of Nanodevices Prepared from Metallic Nanoparticles and Their Role in Controlling Infectious Diseases
Published in Suvardhan Kanchi, Rajasekhar Chokkareddy, Mashallah Rezakazemi, Smart Nanodevices for Point-of-Care Applications, 2022
Gold nanoparticles (Au-NPs) have been generally researched because of their uniqueness particularly in biomedication [73]. In existing research works, green synthesis of gold nanoparticles was achieved using leaf extracts of both Carica papaya and Catharanthus roseus, and the antibacterial activity for biosynthesized gold nanoparticles was tested against pathogens such as S. aureus, E.coli, Proteus vulgaris and Bacillus subtilus, which resulted in exhibiting enhanced antibacterial activity [74]. Anona muricata leaf extract was used for gold nanoparticle synthesis and antimicrobial activity tested against some human pathogenic bacteria and fungi such as Staphylococcus aureus, Clostridium sporogenes, Enterococcus faecalis, Klebsiella pneumonia, Aspergillus flavus, Penecillium camemeri, Fusarium oxysporium and Candida albicans. The Anona muricata mediated gold nanoparticles were reported to result in increasing order of potential antimicrobial activity as the concentration increases [50].
Microbial Remediation of Persistent Organic Pollutants
Published in Narendra Kumar, Vertika Shukla, Persistent Organic Pollutants in the Environment, 2021
Several environmental factors, like ambient pH, temperature, nutrients, and moisture level, play an important role in successful bioremediation; for example, studies show that dehydrohalogenation of lindane to γ-hexachlorocyclohexane takes place in moist soil and is attributed to soil microorganisms such as Bacillus coli and Clostridium sporogenes (Zacharia, 2019). The extent of bioremediation that can be achieved will also depend on the complexity of the target compound and the presence of key factors to key the microbes alive (Cutright and Ziya, 2012). Bioavailability of contaminants to the bacteria has a positive effect on the bioremediation process. Certain studies have found through experiments that bioremediation of soils contaminated with polycyclic aromatic hydrocarbons is limited by the poor availability of these hydrophobic contaminants, but some pollutant-degrading bacteria secrete biosurfactants that increase the aqueous concentration of naphthalene, which indicates that a microorganism can promote solubilization of its substrate, thus promoting contact between microbe and substrate (Deziel et al., 1996, Aislabie et al., 1997). It has also been observed that biosurfactant-producing bacteria are more common in a number of areas with high concentrations of polycyclic aromatic hydrocarbons.
Thermal Sterilization of Foods
Published in Susanta Kumar Das, Madhusweta Das, Fundamentals and Operations in Food Process Engineering, 2019
Susanta Kumar Das, Madhusweta Das
The value of α is extremely large for bacterial spores in the range of 1030–1060 s−1, and E value can be as high as 500 kJ mol−1 (vide Holdsworth, 1997 for details). The value of E ranges from 210 to 418 kJ mol−1 for vegetative cells and spores, which are considerably higher than those of enzymes and vitamins (8.4–84 kJ mol−1). Typical values of k at 121°C for some spore-former bacteria like Bacillus subtilis FS 5230, Bacillus stearothermophilus FS 1518, Clostridium sporogenes PA 3679 are 3.8−2.6, 0.77 and 1.8 min−1, respectively (Aiba et al., 1973). The corresponding value for vegetative cells like Escherichia coli is in the order of 1013 min−1. For other vegetative cells (depending on microorganism), this value varies between 10 and 1010 min−1.
Human and livestock pathogens and their control during composting
Published in Critical Reviews in Environmental Science and Technology, 2022
Enzymes produced by native microorganisms, such as alkaline proteases, are particularly important for several reasons. They are stable and active at high pH and in the presence of surfactants and oxidizing agents. They are produced by bacteria, molds, and yeasts. Most of them are isolated from Bacillus species and fungal species found in composts such as Aspergillus species (Hajji et al., 2007). Most of these enzymes have an optimum pH of 8.0–9.5 and are active between 40 °C and 70 °C (Tremacoldi et al., 2007). Lactococcus lactis subsp. lactis, another thermophilic bacterium, can produce a small peptide called nisin. Nisin has antimicrobial properties against gram-positive bacteria such as Bacillus cereus, Clostridium botulinum, Clostridium sporogenes, Enterococcus spp., Listeria monocytogenes, and Staphylococcus spp. (Cetin-Karaca, 2011). Nisin is stable in thermophilic conditions and has sporostatic properties. meaning that it is capable of inhibiting spore germination. In vegetative cells, nisin forms pores in the cytoplasmic membrane, destroying the cell membrane integrity resulting in leakage of cytoplasmic content (Raybaudi-Massilia et al., 2009).
Synthesis, spectral and structural characterization and biological activity of Cu(II) complexes with 4-(diethylamino)salicylaldehyde and α-diimines
Published in Journal of Coordination Chemistry, 2020
Teodora Dimitrijević, Irena Novaković, Dušanka Radanović, Sladjana B. Novaković, Marko V. Rodić, Katarina Anđelković, Maja Šumar-Ristović
In vitro antibacterial and antifungal activity was tested against four Gram-positive bacteria (Bacillus subtilis ATCC 6633, Clostridium sporogenes ATCC 19404, Kocuria rhizophila ATCC 9341, Staphylococcus aureus ATCC 6538), four Gram-negative bacteria (Proteus hauseri ATCC 13315, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 9027, Salmonella enterica ATCC 13076), and three fungal strains (Aspergillus brasiliensis ATCC 16404, Candida albicans ATCC 10231, Saccharomyces cerevisae ATCC 9763), by the double dilution method in microtiter plates [49]. Mueller Hinton broth was used for determination of antibacterial activity, whereas Sabouraud dextrose broth was used for determination of antifungal activity. One hundred microliters of fresh Mueller Hinton or Sabouraud dextrose broth were added to each well of the plate. Then, 100 μL of the compounds stock solution (10 mg/mL) prepared by dissolving compounds in DMSO was added. Each well was inoculated with 10 μL (106 cells per mL) of bacterial cultures and 10 μL (105 spores per mL) of fungal strains for antibacterial and antifungal determination, respectively. Bacterial strains were incubated on 37 °C for 24 h. Amikacin was used as a positive control, while water served as a negative control. Fungal strains were incubated on 28 °C for 48 h. Fluconazole was used as a positive control, while DMSO as a negative control. The MIC was determined as the lowest concentration that resulted in inhibition of visible microbial growth.
Enhanced fermentative hydrogen production from potato waste by enzymatic pretreatment
Published in Environmental Technology, 2022
Esma Mahfouf Bouchareb, Kerroum Derbal, Rayane Bedri, Souha Menas, Raouf Bouchareb, Nadir Dizge
Aerobic sludge was used as inoculum. It was extracted from the aeration tank of an aerobic digester of a wastewater treatment plant, located in Oued El Athmania, Algeria. Thermal treatment at 90°C for 30 min was applied to the sludge. The thermal treatment was employed to eliminate methanogens bacteria [16]. Thereafter, the sludge was cooled to ambient temperature to select sporulated hydrogen bacteria, such as Clostridium sporogenes [17] and to inhibit the non-hydrogen-producing bacteria. The treated sludge was stored at ±4°C to preserve its characteristics.