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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 on cactus pear grabs attention of food, cosmetic and medical industry
2015-02-18

Cactus pear
Photo: Charl Devenish

The dedicated research and development programme at the UFS on spineless cactus pear (Opuntia ficus-indica) – also known as prickly pear – has grown steadily in both vision and dimension during the past 15 years. Formal cactus pear research at the UFS started with the formation of the Prickly Pear Working Group (PPWG) in June 2002. It has since gone from strength to strength with several MSc dissertations and a PhD thesis as well as popular and scientific publications flowing from this initiative.

According to Prof Wijnand Swart from the Department of Plant Sciences, the UFS is today recognised as a leading institution in the world conducting multi-disciplinary research on spineless cactus pear.

Cactus pear for animal feed

Increasing demands on already scarce water resources in South Africa require alternative sources of animal feed – specifically crops that are more efficient users of water. One alternative with the potential for widespread production is spineless cactus pear. It is 1.14 x more efficient in its use of water than Old man saltbush, 2.8 x more efficient than wheat, 3.75 x more efficient than lucerne and 7.5 x more efficient than rangeland vegetation.

“Studies on the use of sun-dried cactus pear cladodes suggest that it has the potential to provide some 25% of the basic feed resources required by South Africa’s commercial ruminant feed manufacturing sector,” says Prof HO de Waal of the Department of Animal, Wildlife and Grassland Sciences at the UFS.

Until recently, research has focused extensively on the use of cactus pear as drought fodder. However, this is now beginning to shift, with growing interest in the intensive production of spineless cactus pear for other types of animal feed. One example is the spineless cactus pear fruit, produced seasonal, yielding large quantities of fruit in a relatively short period of a few months in summer. Unless kept in cold storage, the fruit cannot be stored for a long period. Therefore, a procedure was developed to combine large volumes of mashed cactus pear fruit with dry hay and straw and preserve it for longer periods as high moisture livestock feed, kuilmoes – a high water content livestock feed similar to silage.

Cactus pear and Pineapple juice
Photo: Charl Devenish

Cactus pear for human consumption

“In addition to its use as a livestock feed, cactus pear is increasingly being cultivated for human consumption. Although the plant can be consumed fresh as a juice or vegetable, significant value can be added through processing. This potential is considerable: the plant can be pickled; preserved as a jam or marmalade; or dried and milled to produce baking flour. It can also serve as a replacement of egg and fat in mayonnaise,” said Dr Maryna de Wit from the Department of Microbial, Biochemical and Food Biotechnology.

The extraction of mucilage from fresh cladodes can form a gelling, emulsifier, and fat-replacing agent commonly found in food products such as mayonnaise and candy. During an information session to the media Dr De Wit and her team conducted a food demonstration to showcase the use of the cladodes in a juice, chicken stir-fry, biscuits and a salad.

The extrusion of cactus pear seed oil provides a further lucrative niche product to the array of uses. These include high-value organic oil for the cosmetic sector, such as soap, hair gel and sun screens.

The cladodes and the fruit also have medicinal uses. It has anti-viral, anti-inflammatory, pain killing and anti-diabetic agents. It is also high in fibre and can lower cholesterol. The fruit also prevents proliferation of cells and suppresses tumour growth and can even help to reduce a hangover.

In South Africa the outdated perception of cactus pears as thorny, alien invaders, is rapidly disappearing. Instead, farmers now recognise that cactus pear can play a vital role as a high yielding, water-efficient, multi-use crop, said Prof de Waal and the members of the Cactus Pear Team.

Facebook photo gallery
Dagbreek interview with Dr Maryna de Wit  

Research on cactus pear (read the full story)

For more information or enquiries contact news@ufs.ac.za

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