Removal of Pathogens (Escherichia coli O157:H7 and Salmonella typhi), and nutrients from wastewater by Lactic Acid bacteria

Outbreaks of various forms of diarrhoea, particularly cholera and typhoid, are a frequent occurrence in low income countries. Poor water sanitation and hygiene practices are frequently implicated for all diarrhoeal out breaks in the low income countries. The present study assessed (i) the probiotic potential of selected strains of lactic acid bacteria in terms of their inhibition activities against Escherichia coli O157:H7 and Salmonella typhi, and the removal of heavy metals in wastewater. The selected lactic acid bacteria had probiotic properties, namely resistance to low pH (pH2 and 3), tolerance to bile salts and sodium chloride, and significant antimicrobial activities against strains of E. coli O157:H7 and S. typhi (p < 0.001). Strains of lactic acid bacteria were shown to modulate the concentration of aqueous Cu, Mn, NH4 + and Zn with a significant net decrease between Day 7 or 10 (p ≤ 0.05). The selected lactic acid bacteria were also shown to deploy biofilms on surfaces of sand particles, which are thought to constitute a mechanism by the lactic acid bacteria to hold and kill E. coli and S. typhi in wastewater. The lactic acid bacteria have exhibited great potential for use in the removal of diarrhoeagenic bacteria and heavy metals from wastewater.

Gold deportment and ore characterisation of the historical Witwatersrand tailings dams with emphasis placed on the sulphides

Thesis (PhD)--Stellenbosch University, 2024.ENGLISH ABSTRACT: The Witwatersrand Basin, discovered in 1881, has yielded over 53,000 tons of native gold hosted in quartz pebble conglomerates. Present gold extraction methods involve comminution and direct cyanidation, resulting in the retention of 5-10 % of residual gold in tailings. Re-mining primarily targets native gold recovery, achieving an average of 30-50 % gold recovery through direct cyanidation. This implies that the remaining 50-70 % of unrecovered gold, along with approximately 30 million tons of residual sulphide waste, is re-dumped to the tailing stream. The Witwatersrand tailings significantly contribute to South Africa's pollution, causing acid mine drainage and deleterious element effluent due to sulphide waste oxidation. The mineralogical distribution of unrecovered gold during tailings reprocessing is inadequately characterized and absent from existing literature. Furthermore, the current body of literature lacks a comprehensive environmental assessment specifically addressing the movement and dispersion of deleterious elements during sulphide oxidation within the Witwatersrand tailings. This PhD research focuses on the ore characterization and mineralogical deportment of unrecovered gold within the Witwatersrand tailings from Klerksdorp, Carletonville, Evander, and Central Rand goldfields. Simultaneously, an environmental assessment explores deleterious element behaviour, retention, and release mechanisms during sulphide oxidation in Witwatersrand tailings dumps. The methodology utilized employs the multi-element, high- resolution, and low-detection capabilities of laser ablation inductively coupled plasma mass spectrometry analysis, combined with an automated mineralogical technique to analyse bulk tailings samples and their operationally defined mineral fractions. Additional analytical methods include aqua regia digestion combined with ICP-MS analysis and fire assay. Mineralogical analysis using optical microscopy, electron microscopy, and X-ray diffraction analysis provides comprehensive insights into the composition and physical properties of minerals. Metallurgical test work, incorporating gravity separation, direct cyanidation, and diagnostic leaching, validates Witwatersrand tailings behaviour in processing scenarios. Results indicate cyanide amenable gold recovery at 14- 61 %, primarily in the form of micron to nano-sized native gold particles. Non-cyanide amenable phases contributing to the refractory behaviour of gold include sulphides (mainly pyrite) and silicates at 4-38 % and 11- 32 %, respectively. In situ pyrite analysis reveals 'invisible' gold within detrital pyrite and arsenian pyrite. These Archean detrital pyrites exhibit grades comparable to auriferous sulphides from surrounding Archean granite- greenstone gold ores on the Kaapvaal craton (up to 2700 ppm). Pyrite also hosts a substantial concentration of deleterious elements, with Co, Au, and Pb strongly leached during pyrite oxidation. However, a significant proportion of As, Ni, Cu, and Zn is retained in the iron oxyhydroxide alteration rims through incorporation and absorption. The study underscores the necessity of addressing 'invisible gold' during beneficiation, proposing tailored leaching parameters and a pretreatment strategy to potentially recover up to 420 tons of gold, thereby contributing to the local economy. Furthermore, the recovery of metals can not only reclaim valuable 'sweetener' by-product metals such as Cu, Co, and Ni but also directly mitigate issues related to deleterious element pollution and acid mine drainage associated with surface tailings dumps. The findings presented in this dissertation represent significant and original contributions to multiple scientific disciplines, notably including geometallurgy, geology, mineral processing, and environmental sciences.AFRIKAANSE OPSOMMING: Die Witwatersrand-bekken, wat in 1881 ontdek is, het al meer as 53,000 ton inheemse goud opgelewer wat gehuisves is in kwarts-kiesel-konglomeraat. Huidige goudonttrekkingsmetodes behels verkleining en direkte sianidasie, wat lei tot die retensie van 5-10% van residuele goud in die storting. Herwinning fokus hoofsaaklik op die herwinning van inheemse goud, met 'n gemiddelde van 30-50% herwinning deur direkte sianidasie. Dit impliseer dat die oorblywende 50-70% van onherwinde goud, saam met sowat 30 miljoen ton residuele sulfiedafval, na die stortvloeistroom hergelei word. Die Witwatersrand-storte dra beduidend by tot die besoedeling van Suid-Afrika, wat suurmyndreinering en nadelige element-effluente veroorsaak as gevolg van die oksidasie van sulfiedafval. Die mineralogiese verspreiding van onherwinde goud tydens die herprosessering van storte, is ontoereikend gekarakteriseer en afwesig in die bestaande literatuur. Verder ontbreek daar 'n omvattende omgewingsassessering in die huidige literatuur wat spesifiek daarop gemik is om die beweging en verspreiding van nadelige element tydens sulfiedoksidasie binne die Witwatersrand-storte aan te spreek. Hierdie doktorale navorsing fokus op die erts-karakterisering en mineralogiese gedrag van onherwinde goud binne die Witwatersrand-storte vanaf Klerksdorp, Carletonville, Evander, en die sentrale Rand-goudvelde. Gelyktydig ondersoek 'n omgewingsassessering die gedrag, retensie en vrylating van nadelige element tydens sulfiedoksidasie in Witwatersrand-storte. Die navorsingsmetodologie maak gebruik van die multi-element, hoë resolusie, en lae opsporingseienskappe van laser-ablasie gekoppel aan induktief gekoppelde plasma massaspektrometrie-analise, sowel as 'n outomatiese mineralogiese tegniek om bulkstortmonsters en hul operasioneel-gedefinieerde minerale te ontleed. Addisionele analitiese metodes sluit aqua regia vertering gekoppel aan ICP-MS-analise, vuurproef, en mineralogiese analise in met behulp van optiese mikroskopie, elektronmikroskopie, en X-straal diffraksie-analise. Metallurgiese toetswerk, wat gravitasieskeiding, direkte sianidasie, en diagnostiese uitloging insluit, bekragtig die gedrag van Witwatersrand-storte in proses-senario's. Resultate dui op sianied-gevoelige goudherwinning van 14- 61%, hoofsaaklik in die vorm van mikro- tot nanogrootte inheemse goudeeltjies. Nie-sianied-gevoelige fases wat bydra tot die refraktêre gedrag van goud, sluit sulfiede (hoofsaaklik piriet) en silikate in, teen onderskeidelik 4- 38% en 11-32%. In situ piriet-analise onthul 'onsigbare' goud binne detritiese piriet en arseniese piriet. Hierdie Argeense detritiese piriete het kwaliteite vergelykbaar met auriferous sulfiede van die omliggende Argeense graniet-groenstof gouderts op die Kaapvaal kraton (tot 2700 ppm). Piriet huisves ook 'n beduidende konsentrasie van nadelige element, waar Co, Au, en Pb sterk uitgeloog word tydens pirietoksidasie. 'n Beduidende proporsie van As, Ni, Cu, en Zn word egter in die ysteroksihidroksied alterasie-rande behou deur inkorporasie en absorpsie. Die studie beklemtoon die noodsaaklikheid om aandag te gee aan 'onsigbare goud' tydens die veredeling, deur op maatgemaakte loggingsparameters en 'n voorbehandelingsstrategie voor te stel om potensieel tot 420 ton goud te herwin, wat tot die plaaslike ekonomie kan bydra. Verder kan die herwinning van nadelige element nie net waardevolle 'versoeter' byproduk-metale soos Cu, Co, en Ni herwin nie, maar kan ook direk probleme met nadelige elementbesoedeling en suurmyndreiniging wat met oppervlakstortings verband hou, verminder. Die bevindinge wat in hierdie proefskrif aangebied word, verteenwoordig beduidende en oorspronklike bydraes tot verskeie wetenskaplike dissiplines, insluitend geometalurgie, geologie, minerale verwerking, en omgewingswetenskappe.Doctorat

Functional and health promoting inherent attributes of Enterococcus hirae F2 as a novel probiotic isolated from the digestive tract of the freshwater fish Catla catla

Probiotic microorganisms are gaining global importance because of their use in the preparation of a nutraceutical or in the treatment of infections. As per the health industry demand, there is an urgent need for exploring new indigenous probiotic strains with its specific origin due to variation in gut microflora, different food habits and specific host-microbial interactions. The main objective of the present study was to isolate and identify a novel probiotic Enterococcus strain from the gut of Catla catla fish and evaluate its potentiality as a potent probiotic. The whole study was designed with the isolation of novel lactic acid bacterial strain from the gut of Catla catla fish with their biochemical and molecular identifications. The potentiality of the isolated strain as a potent probiotic was carried out according to the parameters described in FAD/WHO guidelines for the evaluation of probiotics in food. The isolated strain was confirmed as Enterococcus hirae F2 on the basis of various biochemical and 16s rRNA gene sequencing methods. Enterococcus hirae F2 was able to survive under highly acidic and bile salt concentration with the ability for the production of lipase and Bsh enzyme. It was also able to survive under simulated gastrointestinal conditions with the inhibition ability of various pathogens. The antioxidant potentiality with the cell surface hydrophobicity and cell aggregation ability confirms its potentiality as a potent probiotic. All the results detail the potency of Enterococcus hirae F2 as a novel probiotic for a safer use. The isolation of Enterococcus hirae with probiotic potential from the gut of fish is a new approach and done for the first time. However, the whole study concluded that the isolated strain might be used as a novel probiotic in the food industry for the production of new probiotic products which imparts health benefits to the host

Spoznavanje biokemijskih temeljev endokanabinoidnega sistema

Odkritje endokanabinoidnega sistema (ECS) je bilo temeljnega pomena ne le pri razumevanju učinkov rastlinskih kanabinoidov, amapk je vodilo tudi do precej širšega biokemisjkega delovanja našega telesa in odprlo velike terapevtske potenciale. Fitokanabinoidi in tudi sintetični kanabinoidi delujejo preko našega endokanabinoidnega sistema in razumevanje osnovne biokemije tega ključnega signalnega sistema omogoča vpogled v koristne in terapevtske učinke teh molekul. Na voljo je veliko raziskovalnih in znanstvenih člankov na temo kanabinoidov, ECS ter njihove vloge in vpliva na zdravje in potek bolezni. Številni podatki so tudi zbrani iz epidemioloških raziskav in iz Life science laboratorijev in vsi ti podatki dajejo bolnikom in zdravstvenim delavcem dobre osnove za uporabo kanabinoidov v medicini. Toda razumevanje biokemije ECS ter vloge tega signalnega sistema v človeški fiziologiji je ključ do pravilne uporabe teh močnih molekul

Antibacterial and anticandidal activity of Tylosema esculentum (marama) extracts

Bean and tuber extracts of Tylosema esculentum (marama) - an African creeping plant - were obtained using ethanol, methanol and water. Based on information that T. esculentum is used traditionally for the treatment of various diseases, the antibacterial and anticandidal effects of tuber and bean extracts were investigated. The antimicrobial activity of the extracts was tested on methicillin-resistant Staphylococcus aureus (MRSA, ATCC 6538), Mycobacterium terrae (ATCC 15755), Corynebacterium diphtheriae (clinical) and Candida albicans (ATCC 2091). We performed the broth microdilution test for the determination of the minimum inhibitory concentration (MIC) and a method to determine survival of microorganisms after in vitro co-incubation with the highest concentrations of T. esculentum extracts, followed by assessment of colony counts. Ethanol and methanol (phenolic) bean extracts exhibited higher potency against bacteria and yeast than aqueous extracts. Marama bean seed coat crude ethanolic extract (MSCE) and seed coat polyphenolic fractions, especially soluble-bound fraction (MSCIB), were highly antimicrobial against M. terrae, C. diphtheriae and C. albicans. All marama bean polyphenolic fractions, namely cotyledon acidified methanol fraction (MCAM), seed coat acidified methanol fraction (MSCAM), cotyledon insoluble-bound fraction (MCIB), seed coat insoluble-bound fraction (MSCIB), cotyledon-free polyphenolic fraction (MCFP) and seed coat free polyphenolic fraction (MSCFP) had high antimicrobial effects as shown by low respective MIC values between 0.1 mg/mL and 1 mg/mL. These MIC values were comparable to those of control antimicrobials used: amphotericin B (0.5 mg/mL) and cesfulodin (0.1 mg/mL) against C. diphtheriae, streptomycin (1.0 mg/mL) and gentamicin (0.4 mg/mL) against M. terrae, and amphotericin B (0.05 mg/mL) against C. albicans. Marama seed coat soluble-esterified fraction (MSCS) had closer activity to that of cefsulodin against M. terrae. High amounts of phenolic substances, such as gallic acid, especially in the seed coats, as well as high amounts of phytosterols, lignans, certain fatty acids and peptides (specifically protease inhibitors) in the cotyledons contributed to the observed antibacterial and anticandidal activities. Marama extracts, especially phenolic and crude seed coat extracts, had high multi-species antibacterial and anticandidal activities at concentrations comparable to that of some conventional drugs; these extracts have potential use as microbicides

The role of functional foods, nutraceuticals, and food supplements in intestinal health

New eating habits, actual trends in production and consumption have a healyh, environmental and social impact. The EU is fighting diseases characteristics of a modern age, such as obesity, osteoporosis, cancer, diabetes, allergies and dental problems. Developed countries are also faced with problems relatingto aging populations, high energy foods, and unbalanced diets. The potential of nutraceuticals/functional foods/food supplements in mitigating health problems, especially in the gastrointestinal (GI) tract, is discused. Certain members of gut microflora (e.g., probiotic/protective strains) play a role in the host health due to its involvment in nutritional, immunologic and physiologic functions. The potential mechanisms by which nutraceuticals/functional foods/food supplements may alter a host\u27s health arealso highlighted in this paper. The establishment of novel functional call models of the GI and analytical tools that allow tests in controlled experiments are highly desired for gut research

The Role of Functional Foods, Nutraceuticals, and Food Supplements in Intestinal Health

New eating habits, actual trends in production and consumption have a health, environmental and social impact. The European Union is fighting diseases characteristic of a modern age, such as obesity, osteoporosis, cancer, diabetes, allergies and dental problems. Developed countries are also faced with problems relating to aging populations, high energy foods, and unbalanced diets. The potential of nutraceuticals/functional foods/food supplements in mitigating health problems, especially in the gastrointestinal (GI) tract, is discussed. Certain members of gut microflora (e.g., probiotic/protective strains) play a role in the host health due to its involvement in nutritional, immunologic and physiological functions. The potential mechanisms by which nutraceuticals/functional foods/food supplements may alter a host’s health are also highlighted in this paper. The establishment of novel functional cell models of the GI and analytical tools that allow tests in controlled experiments are highly desired for gut research