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Dr
Basson, Albertus K.
Department: Biochemistry and Microbiology
Active Community Engagement: To be added
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- Annually, approximately 23,000 cases of food poisoning by Staphylococcus aureus enterotoxins are reported worldwide. The aim of this study was to determine the occurrence and characterize S. aureus on beef and beef products in South Africa. Organ meats (n = 169), raw processed meat (n = 110), raw intact (n = 53), and ready-to-eat meats (n = 68) were obtained from 25 retail outlets. S. aureus was isolated and enumerated according to the ISO 6888-1 method. Identification of the strains was performed by MALDI-TOF MS. The antimicrobial resistance was determined using the disc diffusion test. The presence of methicillin-resistance genes and the staphylococcal enterotoxin genes was determined by PCR. Prevalence was low (13/400; CI 1.7–5) and all but one positive sample were from organ meats. Eight isolates were resistant to at least one antibiotic. Two isolates carried the mecC gene. All the isolates tested positive for seg, seh, sei, and sep, whilst 53.8% were positive for sea. None of the isolates was positive for ser, sej, seb, sec, or sed. The prevalence of S. aureus was low, with organ meats being the most contaminated. The presence of mecC-positive MRSA and of enterotoxins warrants further investigation and risk assessment.
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- 2020| Suid-Afrikaanse Akad...A broad range of applications and interesting properties of core-shell nanoparticles (CSNs) such as catalysis, sensors, material chemistry, biology, and water purification have gained the huge interest of most researchers in recent years. The aim of the study was to synthesise Fe@ Cu CSNs nanoparticles using a bioflocculant and to evaluate its potential application in flocculation activity (FA), wastewater treatment, and as an antimicrobial agent. A dosage of 0.2 mg/mL Fe@ Cu CSNs was found to be the most effective with 99% FA and also has an advantage to flocculate at a wider pH range of 3–11 (acidic, neutral and alkaline). Thermostability of the engineered nanomaterials (ENMs) was evaluated between the temperatures range of 60–100 ºC, however, 96% FA was retained, indicating the thermal stability of the ENMs. The addition of cation, Ca2+, further improved the flocculation activity to the highest reading of 99%. The high removal efficiency (RE) of chemical oxygen demand (COD), biochemical oxygen demand (BOD), total nitrogen and phosphate was observed in all wastewater samples examined. The removal efficiency of the dyes was found to be above 93% for all dye samples. The ENMs possess antimicrobial activity against both Grampositive and Gram-negative microorganisms. The Minimal Inhibitory Concentration (MIC) and Bactericidal Minimal Concentration (MBC) were observed at a lower concentration of 1.563 mg/mL. Cell viability against HEK293 and MCF7 was high at the lower concentration; with the increase in concentration the decrease in cell viability was observed.
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- Nanotechnology addresses numerous environmental problems such as wastewater treatment. Ground water, surface water and wastewater that is contaminated by toxic organic, inorganic solutes and pathogenic microorganisms can now be treated through the application of nanotechnology. The study reports iron@copper (Fe@Cu) nanoparticles, iron nanoparticles (FeNPs) and copper nanoparticles (CuNPs) synthesized using a bioflocculant in a green approach technique. Characterization of the as-synthesized materials was achieved using analytical techniques such as Fourier transform-Infrared spectroscopy (FT-IR), Thermogravimetric analysis (TGA), Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM), UV-Vis spectroscopy (UV-Vis) and X-ray diffraction (XRD). The presence of hydroxyl (–OH) and amine (–NH2) groups was shown by FT-IR spectroscopy studies and the as-synthesized material was shown to be thermostable. Elements such as oxygen, carbon, iron and copper were found to be abundant in Wt%. Absorption peaks were found between 200 and 390 nm wavelength and diffraction peaks at 2θ –29°, 33° and 35° for FeNPs, CuNPs and Fe@Cu, respectively. In their application, the effect of various parameters on the flocculation activity were evaluated. Both the CuNPs and (Fe@Cu) nanoparticles have shown the best flocculation activity at a concentration of 0.2 mg/mL with over 90% activity, while the dosage size with a concentration of 0.4 mg/mL was optimal for FeNPs. The FeNPs were found to be cation dependent, while CuNPs and Fe@Cu nanoparticles flocculate in the absence of a cation and flocculate both in acidic and alkaline pH. All the synthesized nanoparticles are thermostable and maintain flocculation activity above 80% at 100 °C. Both the Fe@Cu and CuNPs were found to be effective in removing dyes with the removal efficiency above 89% and were found to be effective in removal of chemical oxygen demand (COD) and biochemical oxygen demand (BOD) in Mzingazi river water and coal mine wastewater with over 80% removal efficiency. Moreover, the synthesized nanoparticles showed some remarkable antimicrobial properties when evaluated against Gram-positive and Gram-negative bacteria. The as-synthesized material was found to be safe to use at low concentration when verified against human embryonic cells (HEK293) and breast cancer cells (MCF7) and biodegradable.
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- Green synthesis of core–shell nanoparticles is gaining importance nowadays as it is viewed as being environmental friendly and cost effective. The present study aimed to synthesize iron@copper core–shell nanoparticles using a polysaccharide-based bioflocculant from Alcalegenis faecalis and to evaluate its efficiency in dye removal and river water and domestic wastewater treatment. The synthesized samples were characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, transmission electron microscopy, and UV-Vis spectroscopy analysis. To optimize the best concentration for core–shell formation, different ratios of iron to copper were prepared. Sample 1 (S1) contained 1:3 iron to copper (Fe 25%–Cu 75%), sample 2 (S2) contained 1:1 iron to copper (Fe 50%–Cu 50%), and the third sample (S3) contained 3:1 iron to copper (Fe 75%–Cu 25%). The flocculation activity (FA) was above 98% at 0.2 mg/mL for all the samples and the samples flocculated well under acidic, alkaline, and neutral pH conditions. Sample 3 was shown to be thermostable, with flocculation activity above 90%, and samples 2 and 1 were also thermostable, but the flocculation decreased to 87 at 100 °C. All three samples revealed some remarkable properties for staining dye removal as the removal efficiency was above 89% for all dyes tested. The synthesized core–shell nanoparticles could remove nutrients such as total nitrogen and phosphate in both domestic wastewater and Mzingazi river water. Furthermore, high removal efficiency for chemical oxygen demand (COD) and biological oxygen demand (BOD) was also observed.
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- There has been great progress in the ‘green’ chemistry approach for the synthesis of nanoparticles in recent years. Nanoparticles have gained special significance due to their unique properties. Herein we report a bioflocculant facilitated eco-friendly synthesis of copper nanoparticles (CuNPs). The copper nanoparticles were successfully synthesized through the reduction of copper sulphate (3 mM) solution by the bioflocculant (0.5 g). The synthesized nanoparticles were characterized by Scanning electron microscope equipped with elementary detector (SEM), X-ray diffractometer (XRD), Fourier Transform Infrared Spectrophotometer (FT-IR), Transmission electron microscopy (TEM), and UV spectroscope. CuNPs were applied in the treatment of both the domestic and industrial wastewater, removal of dyes and were confirmed for the antimicrobial effect against both Gram-negative and Gram-positive microorganisms. The synthesized nanoparticles showed great potential for industrial application when compared to the chemical flocculant. In comparison to FeCl3 and bioflocculant, the nanoparticles were found to be effective in BOD and COD removal in coalmine wastewater samples. The highest flocculating activity and removal efficiency was observed at the lowest dosage of 0.2 mg/mL. Moreover, both the Minimal inhibitory concentration (MIC) and Minimal bactericidal concentration (MBC) were observed at the concertation of 12.5 μL.
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