http://hdl.handle.net/10386/2800 Sun, 12 Apr 2026 12:04:51 GMT 2026-04-12T12:04:51Z http://hdl.handle.net/10386/4697 Green derived zinc oxide (ZnO) for the degradation of dyes from wastewater and their antimicrobial activity: a review Mahlaule-Glory, Louisah M.; Hintsho-Mbita, Nomso C. The quest for eco-friendly synthetic routes that can be used for the development of multifunctional materials, in particular for water treatment, has reinforced the use of plant extracts as replacement solvents in their use as reducing and capping agents during the synthesis of green derived materials. Amongst the various nanoparticles, Zinc Oxide (ZnO) has emerged as one of the preferred candidates for photocatalysis due to its optical properties. Moreover, ZnO has also been reported to possess antimicrobial properties against various bacterial strains such as E. coli and S. aureus. In this review, various types of pollutants including organic dyes and natural pollutants are discussed. The treatment methods that are used to purify wastewater with their limitations are highlighted. The distinguishing properties of ZnO are clearly outlined and defined, not to mention the performance of ZnO as a green derived photocatalyst and an antimicrobial agent, as well. Lastly, an overview is given of the challenges and possible further perspectives Journal article published in Catalysts 2022, 12, 833. Sat, 01 Jan 2022 00:00:00 GMT http://hdl.handle.net/10386/4697 2022-01-01T00:00:00Z http://hdl.handle.net/10386/4691 Isolation and optimisation of culture conditions for a marine bioflocculant-producing bacterium and application of its bioflocculant in wastewater treatment Selepe, Tlou Nelson; Maliehe, Tsolanku Sidney; Moganedi, Kgabo; Masoko, Peter; Mlaudzi, Vusimuzi The application of bioflocculants has become an alternative to that of chemical flocculants in wastewater treatment due to their environmental friendliness and non-toxic effects. This study aimed at isolating a bioflocculant-producing bacterium from marine water, optimisation of its culture conditions, and investigation of the removal efficiency of its bioflocculant on pollutants in wastewater. The bacterium was identified by 16S rRNA gene analysis. Optimal carbon and nitrogen sources, inoculum size, temperature, pH, and time were determined by the one-factor-at-a-time assay. The cytotoxicity of the bioflocculant was assessed on African green monkey kidney and bovine dermis cells using a tetrazolium-based columetric (MTT) method. Its removal efficiencies on chemical oxygen demand (COD), biological oxygen demand (BOD) and sulphur were determined using the Jar test method. The bacterial isolate was identified as Ochrobactrum oryzae AB84113. A maximum flocculating activity of 92% and a yield of 3.768 g/L were obtained when a 1% (v/v) inoculum size was used in the presence of starch and yeast extract at pH 7, 30 ◦C, and after 72 h of cultivation. The bioflocculant demonstrated non-cytotoxic effects on bovine dermis and African green monkey kidney cells. The bioflocculant removed 98% COD, 91% BOD and 86% of Sulphur. The bioflocculant has potential for pollutant removal from industrial wastewater. Journal article published in International Journal of Environment Research. Public Health 2022, 19, 10237 Sat, 01 Jan 2022 00:00:00 GMT http://hdl.handle.net/10386/4691 2022-01-01T00:00:00Z http://hdl.handle.net/10386/4037 Molecular and phenotypic characterization of heterorhabditis indica (Nematoda: Rhabditida) nematodes isolated during a survey of agricultural soils in Western Uttar Pradesh, India Bhat, Aashaq Hussain; Chaubey, Ashok Kumar; Shokoohi, Ebrahim; Machado, Ricardo A. R. Introduction Entomopathogenic nematodes (EPNs) are important biocontrol agents of insect pests. To increase the availability of locally adapted entomopathogenic nematode isolates for biocontrol programs, a survey of several agricultural soils in Western Uttar Pradesh, India was conducted. Materials and methods Eight hundred and sixty soil samples from the districts Meerut, Bulandshahr, Baghpat, and Bijnor were collected and examined for the presence of entomopathogenic nematodos using the “Galleria baiting method”. Steinernema and Heterorhabditis nematodes were recovered. The isolated Heterorhabditis nematodes were molecularly, and morphologically characterized, and their biocontrol potential was evaluated against Spodoptera litura. Finally, the geographical distribution of entomopathogenic nematodes was studied based on the analysis of ITS GenBank records. Results A small proportion of the collected soil samples were positive for Heterorhabditis and Steinernema nematodes. Twelve soil samples were positive for the presence of Heterorhabditis nematodes, and 29 samples were positive for Steinernema. The Heterorhabditis nematodes were identified as Heterorhabditis indica based on morphological, morphometrical and molecular analyses. No other species of Heterorhabditis were isolated from the soil samples analyzed, suggesting that this species is dominant in the western part of Uttar Pradesh, India. The morphology of the nematode isolates was somewhat similar to the morphology of the H. indica isolate used for the original description of this species, with a notable exception mucrons were present in the hermaphrodite and female specimens we collected, but this structure was not observed in the specimens used for the original description of the species. Principal component analyses (PCA) show small inter- and intraspecific morphological variability between the nematodes species of the “Indica” clade. The insecticide properties of one isolate, CH7, were evaluated against Spodoptera litura, and the results show that this isolate effectively killed this pest under laboratory conditions, demonstrating its potential as a biocontrol agent. Conclusion This study sets the basis for establishing new biocontrol agents to be used in future pest management programs in India. Journal article published in Acta Parasitologica (2021) 66:236–252 Fri, 01 Jan 2021 00:00:00 GMT http://hdl.handle.net/10386/4037 2021-01-01T00:00:00Z http://hdl.handle.net/10386/4026 Heavy metal and metalloid contamination in the sediments of the Spekboom River, South Africa Addo-Bediako, Abraham; Nukeri, Sophy; Kekana, Millicent The impact of anthropogenic activities such as mining, agriculture and urbanization is causing heavy metal contamination in many freshwater ecosystems. The concentrations of eight elements (As, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in the Spekboom River, South Africa, were studied using enrichment factor (EF) and geo-accumulation index ( Igeo) to assess the extent of pollution in the river. Sediment samples were collected and analyzed using sequential inductively coupled plasma—optical emission spectrometry. The results showed deterioration of the sediment quality with high concentration of Cr and Ni at all the sites, this is a reflection of contamination from the various anthropogenic activities in the area. The current levels of Cr and Ni could be detrimental to the river and may pose a serious threat to the aquatic organisms and humans, as the sediment could act as a secondary source of metal pollution in the water. It is therefore recommended that urgent action should be taken to control effluents from anthropogenic activities to the river in order to prevent further pollution. Journal article published in the Journal of Applied Water Science (2021) 11:133 Fri, 01 Jan 2021 00:00:00 GMT http://hdl.handle.net/10386/4026 2021-01-01T00:00:00Z