Marelize Botes

Marelize Botes
Stellenbosch University | SUN · Department of Microbiology

PhD Microbiology

About

28
Publications
22,149
Reads
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1,278
Citations
Citations since 2016
12 Research Items
838 Citations
2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150
Additional affiliations
January 2009 - December 2013
Stellenbosch University
Position
  • PostDoc Position

Publications

Publications (28)
Article
Full-text available
Toxic phytoplankton in the aquatic ecosystems are dynamic, affecting water quality. It remains unclear as to how possible toxic phytoplankton assemblages vary vertically and temporally in Swakoppoort and Von Bach dams, located in a dry subtropical desert region in central Namibia. The following variables were analyzed: pH, Secchi depths, turbidity,...
Article
Full-text available
The notion of a “biobased economy” in the context of a developing country such as South Africa (SA) necessitates the development of technologies that utilize sustainable feedstocks, have simple and robust operations, are feasible at small scale and produce a variety of valuable bioproducts, thus fitting the biorefinery concept. This case study focu...
Article
Full-text available
Characterisation of pomace from citrus fruits, grapes and apples has shown to be rich in compounds that contain untapped energetic value with potential to serve as feedstock for biochemical and biofuel production. This study aimed to investigate the potential of recovering the energy in citrus (CtP), grape (GP) and apple (AP) pomace by extraruminal...
Article
Ecological restorations of reservoirs are implemented worldwide; however, minimal successes are reported and understood for warmer African lakes like Swakoppoort Dam, Namibia. The objectives of the study were (a) to establish the effectiveness of the two control measures in reducing cyanobacteria growths in comparison with untreated control areas a...
Article
In vitro digestion of pomace with DMSO cryo-rumen fluid is similar to fresh rumen. • Extraruminal fermentations with glycerol cryo-rumen lead to elevated VFA yields. • Fermentation products of DMSO cryo-rumen have distribution similar to fresh rumen. • Unweighted unifrac distance metrics clustered DMSO cryo-rumen with fresh rumen. A R T I C L E I N...
Article
Full-text available
Water from the Blyderiver dam in the Mpumalanga province, South Africa is used for gravity-fed irrigation. Biofilm development in the pipelines causes an increase in pipeline surface roughness, reduced hydraulic capacity, and water delivery below design capacity. The role of manganese (Mn) concentration on biofilm development is of interest, since...
Article
Biomass derived from low-value, high-volume invasive plant species is an attractive, alternative feedstock to produce biofuels and biochemicals. This study aimed to use the carboxylate platform to valorize the invasive leguminous shrub, Prosopis juliflora (Mesquite), by utilizing in vitro rumen fermentations without chemical pretreatment to produce...
Article
Full-text available
Freshwater resources in semi-arid countries are under constant threat from pollution. One of the major pollutants is acid mine drainage (AMD), which not only lowers the pH of the water, but contains high sulphuric acid and high metal concentrations. Bacteria and algae are the first organisms to respond to stressors such as reduced pH and high metal...
Article
Full-text available
Microorganism growth in industrial systems is controlled through the use of biocides and biodispersants. There is, however, no simple means of determining the efficacy of these control mechanisms, but it is currently tested using complex bacterial culturing techniques. Biolog Ecoplates® have been used to detect bacterial population changes in vario...
Article
Aims: To utilize a three-tiered approach to provide insight into the microbial community structure, the spatial distribution and the metabolic capabilities of organisms of a biofilm in the two towers of a high rate biological contact reactor treating winery wastewater. Methods and results: Next generation sequencing indicated that bacteria prima...
Article
Full-text available
Domestic wastewater sludge can serve as a carbon source in the passive biotic treatment of acid mine drainage (AMD) in microbial bioreactors to create anaerobic conditions for the removal of sulphate, chemical oxygen demand (COD) and pH neutralization. A synthetic medium simulating domestic wastewater sludge was used in AMD treatment in a ratio of...
Article
Full-text available
Requirements for successful biological treatment of acid mine drainage (AMD) rely on the reduction of sulphates by microorganisms using a suitable organic carbon source. Various carbon sources, such as domestic wastewater sludge, have previously been used in the semi-passive biological treatment of AMD. Domestic wastewater sludge is however highly...
Article
Full-text available
The effect of ultrasound on the growth of M. aeruginosa confirmed to contain gas vacuoles and on a laboratory culture with no gas vacuoles was investigated. Both cultures were treated continuously for 9 d with an ultrasonic flow device. To evaluate the influence of ultrasound during the treatment, the chlorophyll-a concentration was measured daily....
Article
BACKGROUND: Chemical methods used to control biofilm formation in filtration systems are not always effective. Two commercially available proteases and an amylase were immobilized onto polymer nanofibers that are used in the production of filtration membranes. RESULTS: The enzymes were immobilized onto poly acrylonitrile nanofibers that were chemic...
Article
Horse is a hindgut fermenter, i.e. most microbial activities take place in the large intestine which constitutes approximately 60 per cent of the gastro-intestinal tract (GIT). The feed reaches the large intestine after approximately 3 h and is fermented for 36–48 h in the caecum. This rate of transition is only possible if the roughage component o...
Article
Full-text available
The occurrence of microorganisms in water due to contamination is a health risk and control thereof is a necessity. Conventional detection methods may be misleading and do not provide rapid results allowing for immediate action. The quantitative polymerase chain reaction (qPCR) method has proven to be an effective tool to detect and quantify microo...
Article
Full-text available
Lactobacillus equigenerosi strain Le1, a natural inhabitant of the equine gastrointestinal tract, survived pH 3.0 and incubation in the presence of 1.5% (wt/vol) bile salts for at least 2 h. Strain Le1 showed 8% cell surface hydrophobicity, 60% auto-aggregation, and 47% coaggregation with Clostridium difficile C6. Only 1% of the cells adhered to vi...
Article
Full-text available
Biofouling is a concern in the water industry due to the impact it has on maintainence of system functioning and the cost involved for prevention. Mechanical and chemical methods such as the application of biocides currently used to control biofouling are not always effective. The need for alternative methods for the prevention of biofouling theref...
Article
Full-text available
Lactobacillus plantarum 24, isolated from marula fruit grows at pH 4.0 and tolerates acid levels and bile concentrations normally present in the human gastro-intestinal tract. Wistar rats that have been administered L. plantarum 24 showed no signs of discomfort or abnormal behavior. Tissue samples from the liver, spleen and intestine appeared norma...
Article
Full-text available
Plantaricin 423, produced by Lactobacillus plantarum 423, was encapsulated in nanofibers that were produced by the electrospinning of 18% (w/v) polyethylene oxide (200 000Da). The average diameter of the nanofibers was 288nm. Plantaricin 423 activity decreased from 51 200 AU/ml to 25 600 AU/ml and from 204 800AU/ml to 51 200 AU/ml after electrospin...
Article
Full-text available
Lactic acid bacteria (LAB) have received considerable attention as probiotics over the past few years. This concept has grown from traditional dairy products to a profitable market of probiotic health supplements and functional foods. Extensive research is done on novel potential probiotic strains, with specific emphasis on their health benefits an...
Article
Full-text available
Electrospun nanofibers and nanobiocides show potential in the improvement of water filtration membranes. Biofouling of membranes caused by the bacterial load in water reduces the quality of drinking water and has become a major problem. Several studies showed inhibition of these bacteria after exposure to nanofibers with functionalized surfaces. Na...
Article
Enterococcus mundtii ST4SA and Lactobacillus plantarum 423 produce bacteriocins with activity against a number of Gram-positive and Gram-negative bacteria. Both strains survived intestinal conditions simulated in a gastro-intestinal model (GIM) with infant milk formulations as substrate and prevented the growth of Listeria monocytogenes ScottA. The...
Article
Full-text available
Adhesion of Enterococcus mundtii ST4SA and Lactobacillus plantarum 423 to Caco-2 (human carcinoma epithelial) cells was visualized by fluorescent staining. Both strains showed good adhesion compared to L. casei MB1, L. casei Shirota, L. johnsonii La1 and L. rhamnosus GG. No correlation was found between hydrophobicity, aggregation and adhesion to C...
Article
To evaluate the probiotic properties of strains isolated from boza, a traditional beverage produced from cereals. The strains survived low pH conditions (pH 3.0), grew well at pH 9.0 and were not inhibited by the presence of 0.3% (w/v) oxbile. Cytotoxicity levels of the bacteriocins, expressed as CC(50), ranged from 38 to 3776 microg ml(-1). Bacter...
Article
To determine the resistance of Lactococcus lactis ssp. lactis HV219 to acids, bile, antibiotics, inflammatory drugs and spermicides, compare adsorption of the strain to bacteria and Caco-2 cells under stress, and evaluate the antimicrobial activity of bacteriocin HV219. Bacteriocin HV219 activity against Gram-positive and Gram-negative bacteria was...

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Project
Here we propose a novel supplemental low-resource approach for broad community-wide surveillance of SARS-CoV-2 infection prevalence. We aim for a real-time Covid-19 risk prediction platform for community-wide diagnostics via wastewater-based epidemiology. Disease markers present in domestic wastewater can reveal the health status of contributing population, and we propose that this includes the infection prevalence by SARS-CoV-2. Real-time spatiotemporal estimation of this novel coronavirus in urban water across several sites in South Africa (Cape Town) and Nigeria (Lagos) will provide a broad picture of community infection prevalence, even for asymptomatic cases, as well as the level of acquired immunity, thus identifying hotspots for priority testing, contact-tracing and quarantine and will provide more accurate projections of the spread of the virus and the infection fatality rate. As communities contribute directly to wastewater, we will be able to estimate true infection rate at the community level, including also asymptomatic and pre-symptomatic people. The virus loading levels will be used to establish status and time trends. This would enable rapid identification of hot spots for management via targeted intervention measures and potentially support important decisions regarding entry into and exit from ‘lockdown’ periods as well as focussed screening of selected communities.