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09 December 2022 | Story Leonie Bolleurs | Photo Leonie Bolleurs
Dr Refilwe Mogale
Dr Refilwe Mogale received her PhD in Chemistry. She is fascinated by the ability of chemistry and science in general to solve some of the world’s most pressing issues, such as water scarcity.

“Chemistry chose me,” says Dr Refilwe Mogale, who wanted to enrol for Psychology years ago when she decided to study at the University of the Free State (UFS). 

“On the day of registration, however, as I was standing in the queue, something inside me said this was not the right choice for me. Ultimately, I chose my second option, which was a BSc degree majoring in biology, physics, and chemistry.”

“Once I started the BSc programme, I gravitated towards chemistry, and as difficult as it was juggling classes and six-hour practical sessions, I loved it. I am fascinated by the ability of chemistry and science in general to solve some of the world’s most pressing issues, such as water scarcity, alternative generation, access to antibacterial hygiene products, as well as novel strategies to cure diseases, among many other things.”

The UFS awarded Dr Mogale a PhD in Chemistry on 9 December 2022.

Addressing a global challenge

Being passionate about applied chemistry – where scientific research can be used to create products to address everyday problems – Dr Mogale focused her thesis on Aluminium- and Zirconium-based metal organic frameworks with azobenzene and stilbene dicarboxylate ligands for use in wastewater treatment. 

She has also published multiple articles on topics of environmental chemistry and wastewater management in international journals. 

Dr Mogale is of the opinion that water pollution by financially lucrative industries and access to clean drinkable water is one of our planet’s most challenging environmental and health issues. “The waste generated by some of the industries that contribute heavily to our country’s economy, such as the textile, agricultural, and medical industries, may end up in the limited drinking water resources we have. I chose my research topic because I wanted to positively contribute to this global challenge,” she says.

“My research was based on making highly porous metal-organic frameworks (MOF) to be used in the wastewater treatment technique called adsorption,” explains Dr Mogale, describing MOFs as “really cool three-dimensional ‘sponges’ that can suck up very high amounts of gases and pollutants, trapping them in their pores. These trapped materials can later be released from the pores to be re-used when MOFs are exposed to certain stimuli.”

She continues, “Low cost and simplicity make this method attractive for industrial use. Considering our current energy crisis, other methods are not ideal, since they require large amounts of energy.” 

Focused on developing highly effective adsorbent for wastewater purification systems, Dr Mogale synthesised a novel MOF with one of the highest adsorption capacities compared to existing counterparts.

According to her, should MOFs with their incredibly high surface areas – which allow them to absorb more waste than their existing counterparts – be implemented in wastewater purification systems, they would be able to address the environmental issue of water pollution and the health issue of access to drinkable water.

Tackling everyday societal issues

She is currently doing a postdoctoral fellowship in the UFS Department of Chemistry – to broaden her knowledge in chemistry beyond MOFs. Her plans are, however, to transition to industry and ultimately entrepreneurship, where she will be able to develop scientific products that can tackle everyday societal issues. 

Dr Mogale dreams of adding value to society by practically contributing to the water crisis issue through the development of low-cost water generation and purification products.

News Archive

Research eradicates bacteria from avocado facility
2017-01-17

 Description: Listeria monocytogenes Tags: Listeria monocytogenes

Listeria monocytogenes as seen under an electron
microscope. The photo was taken with a transmission
electron microscope at the microscopy unit of the UFS.
Bacteriophages (lollipop-like structures) can be seen
next to the bacterial cells.
Photo: Supplied

“The aim of my project was to identify and characterise the contamination problem in an avocado-processing facility and then to find a solution,” said Dr Amy Strydom, postdoctoral fellow in the Department of Microbial Biochemical and Food Biotechnology at the University of the Free State (UFS).

Her PhD, “Control of Listeria monocytogenes in an Avocado-processing Facility”, aimed to identify and characterise the contamination problem in a facility where avocados were processed into guacamole. Dr Strydom completed her MSc in food science in 2009 at Stellenbosch University and this was the catalyst for her starting her PhD in microbiology in 2012 at the UFS. The research was conducted over a period of four years and she graduated in 2016. The research project was funded by the National Research Foundation.

The opportunity to work closely with the food industry further motivated Dr Strydom to conduct her research. The research has made a significant contribution to a food producer (avocado facility) that will sell products that are not contaminated with any pathogens. The public will then buy food that is safe for human consumption.


What is Listeria monocytogenes?

Listeria monocytogenes is a food-borne pathogenic bacterium. When a food product is contaminated with L. monocytogenes, it will not be altered in ways that are obvious to the consumer, such as taste and smell. When ingested, however, it can cause a wide range of illnesses in people with impaired immune systems. “Risk groups include newborn babies, the elderly, and people suffering from diseases that weaken their immune systems,” Dr Strydom said. The processing adjustments based on her findings resulted in decreased numbers of Listeria in the facility.

The bacteria can also survive and grow at refrigeration temperatures, making them dangerous food pathogens, organisms which can cause illnesses [in humans]. Dr Strydom worked closely with the facility and developed an in-house monitoring system by means of which the facility could test their products and the processing environment. She also evaluated bacteriophages as a biological control agent in the processing facility. Bacteriophages are viruses that can only infect specific strains of bacteria. Despite bacteriophage products specifically intended for the use of controlling L. monocytogenes being commercially available in the food industry, Dr Strydom found that only 26% of the L. monocytogenes population in the facility was destroyed by the ListexP100TM product. “I concluded that the genetic diversity of the bacteria in the facility was too high and that the bacteriophages could not be used as a control measure. However, there is much we do not understand about bacteriophages, and with a few adjustments, we might be able to use them in the food industry.”

Microbiological and molecular characterisation of L. monocytogenes

The bacteria were isolated and purified using basic microbiological culturing. Characterisation was done based on specific genes present in the bacterial genome. “I amplified these genes with polymerase chain reaction (PCR), using various primers targeting these specific genes,” Dr Strydom said. Some amplification results were analysed with a subsequent restriction digestion where the genes were cut in specific areas with enzymes to create fragments. The lengths of these fragments can be used to differentiate between strains. “I also compared the whole genomes of some of the bacterial strains.” The bacteriophages were then isolated from waste water samples at the facility using the isolated bacterial strains. “However, I was not able to isolate a bacteriophage that could infect the bacteria in the facility.

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