When most people see a wattle tree, they think of firewood or a nuisance to the environment. For Prof Lizette Erasmus and her colleagues (Prof Deon Visser and Prof Marietjie Schutte-Smith) in the UFS Department of Chemistry, wattle is pure potential. This hardy invader, often blamed for choking ecosystems, has inspired one of their most exciting projects yet: transforming spent wattle bark and other plant waste into biodegradable, super-absorbent polymers that can hold water and slowly release nutrients over time. The result? A natural, water-saving fertiliser that helps crops thrive, even in dry conditions.
On top of the wattle bark project, they developed biochar from agricultural and forestry by-products to revitalise nutrient-depleted soils, and wood vinegar to act as a natural growth stimulant and soil conditioner. Then they combined these elements into what she calls the ‘ultimate fertiliser’ – a mix that improves long-term soil health and resilience.
Chemistry that matters
It is chemistry that gives back to the earth; and this is just one example of how she and her colleagues are turning waste into worth. “By applying the principles of green chemistry and circular economy, we’re proving that waste can become a starting point for something useful, not an end.”
This philosophy runs through all her work. “My approach to sustainability is rooted in both curiosity and responsibility,” she says. “Growing up surrounded by nature, I developed a strong awareness of how human activity affects our environment. As a chemist, I’ve always believed that chemistry should be part of the solution, not the problem.”
The idea of doing research that matters started in the department’s tearoom. “We were talking about publishing papers and doing great science,” she recalls, “but we wanted to do more, to have an impact. That conversation sparked many of the projects we’re doing today.” They enjoy the process, too. “Ons speel lekker,” she says with a smile. “We have too many ideas and not enough time. That’s what makes science exciting.”
One of those big ideas came from a surprising source: electronic waste. Inside old phones and laptops lie an unexpected treasure: gold. “There’s 95% more gold in e-waste per ton than in ore,” she notes. They have developed bio-based absorbents that extract gold and other valuable metals from discarded electronics in an environmentally friendly way. “It’s a green route for resource recovery,” she says, showing how chemistry can literally turn trash into treasure.
The group also recycles construction and demolition waste to create low-cost materials that remove contaminants from wastewater, including runoff from farms and even sewage. These projects support clean water and healthy soil while helping rural communities. Similarly, they have created absorbent sponges that remove oil spills without soaking up water, offering solutions for industrial and environmental clean-ups.
In another innovative project, they are working with the mycelium of mushrooms; the intricate root-like network beneath the surface. Mycelium contains high levels of chitin, a natural polymer that is usually extracted from crab or crayfish shells in a costly, resource-intensive process. By using mushrooms instead, the researchers have found a greener way to produce chitosan, which has promising uses in medicine and skincare.
Building on this spirit of innovation, the group has also turned their attention to the black soldier fly, an insect increasingly used in animal feed. “The inside of the fly is great for feed, but the shell is rich in chitin and melanin,” Prof Erasmus explains. “We can use these compounds in slow-release drug delivery systems and for wound care.”
Sustainability that is innovative and inclusive
Wool, too, has become a new frontier. Working with Gerber & Co., they are developing techniques to make wool machine washable – a process called anti-felting – while also exploring its use in soundproofing, thermal insulation, and ‘roll-out’ grass mats. They are also extracting keratin from waste wool as a fine powder to create advanced composites that could aid in tissue repair, tooth remineralisation, or even self-healing materials.
Her dream is to see these efforts grow into something even bigger: a national centre for circular and nature-inspired chemistry, where scientists, students, and communities can work side by side to transform waste into valuable materials. “The goal is to make sustainability both innovative and inclusive,” she says.
The message is clear: in the right hands, even waste can shine.