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25 August 2025 | Story Martinette Brits | Photo Stephen Collett
Prof Elizabeth Erasmus
Prof Elizabeth Erasmus during her inaugural lecture, Molecules of Change: Chemistry for a Better Tomorrow, on 20 August, highlighting how innovative chemistry can turn waste into value and promote sustainable solutions.

With climate change, resource scarcity, and environmental pollution among the most pressing challenges of our time, Prof Elizabeth (Lizette) Erasmus used her inaugural lecture on Wednesday, 20 August to show how chemistry can provide powerful, practical answers. In her lecture, Molecules of Change: Chemistry for a Better Tomorrow, she traced her journey from fundamental research to pioneering innovations that turn waste into value, protect ecosystems, and improve food security.

During her talk, Prof Erasmus – Researcher in the Department of Chemistry – recalled a moment in 2018 that reshaped her career trajectory. While preparing a Sasol research grant on copper oxide nanoparticles, an entrepreneur assisting with the proposal posed a deceptively simple challenge: “So what?” “Although upsetting at first, those two words completely reshaped my outlook,” she explained. “They inspired my journey from purely academic chemistry towards more applied, impactful research – with the mission of not only advancing science, but of also improving society and the environment.”

 

From fundamental science to global solutions

Prof Erasmus began her career in organometallic chemistry, preparing and characterising complex molecules to understand their reactivity and physical properties. Later, her focus shifted to heterogeneous catalysis, where she explored nanomaterials and surface chemistry.

Her research has since evolved towards developing sustainable technologies that address urgent global challenges. One example is agricultural innovation: using green solvents to extract cellulose from wattle tree bark to create biodegradable superabsorbent polymers. “Unlike the polyacrylates in baby diapers, these SAPs degrade into nutrients for soil microbes and plants,” she explained. “By loading them with fertiliser, we develop slow-release, water-retaining materials that improve agricultural sustainability.”

Other projects include producing biochar to restore degraded soils, creating natural growth enhancers such as wood vinegar, and designing an ‘ultimate fertiliser’ that combines these products for long-term soil health. Her group also works on environmental remediation, developing hydrophobic sponges to absorb oil spills, repurposing building waste to clean polluted water, and using innovative chemistry to convert carbon dioxide into valuable products.

“We are even looking at one of the fastest-growing waste streams: e-waste,” Prof Erasmus noted. “With more gold per ton than natural ore, e-waste represents both a challenge and an opportunity. By developing porous absorbent materials, we can selectively capture and reduce gold ions directly to metallic gold – recovering a precious resource from waste.”

She concluded by crediting her team and collaborators: “This, however, is only the tip of the iceberg. The bulk of the work lies beneath the surface, carried out by dedicated students, collaborators, mentors, colleagues, friends, and family. I owe them my deepest gratitude, for they are the ones who truly sustain this journey of transforming chemistry into solutions for a better world.”

 

About Prof Erasmus

Prof Elizabeth (Lizette) Erasmus obtained all her degrees at the University of the Free State: a BSc (2001), BSc Honours in Chemistry (2002), MSc in Chemistry (2003), and a PhD in Chemistry (2005). She has published more than 80 research papers, holds an H-index of 21, and has extensive experience in supervising MSc and PhD students.

After serving as a senior researcher at the CSIR, she returned to academia at the UFS, where her international collaborations in the Netherlands and at UC Davis broadened her focus from organometallic chemistry to heterogeneous catalysis and nanochemistry. Her expertise spans organometallic chemistry, electrochemistry, surface characterisation, and nanomaterials.

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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