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UFS researchers using mushrooms to clean contaminated water

28 August 2024 | Story André Damons | Photo Supplied

In an effort to alleviate the burden of water contamination, Prof Patricks Voua Otomo, Associate Professor in the Department of Zoology and Entomology at the University of the Free (UFS) is researching how mushrooms can be used to significantly reduce the toxicity of water.

The degradation of river systems in South Africa has been linked primarily to the inability of municipalities to properly treat wastewater. According to the 2022 Green Drop Report, out of the existing 850 wastewater systems across 90 municipalities, only 23 (or less than 3%) qualified for the Green Drop Certification. This underscores the depth and breadth of the wastewater treatment crisis in South Africa and its potential implications for human and environmental health.

In 2030, billions of people will still lack access to safe water, sanitation and hygiene services – the most basic human need for health and well-being. Target 6.1 of the United Nations (UN) Sustainable Development Goals (SDGs) – SDG 6 – aims to achieve universal and equitable access to safe and affordable drinking water for all, while target 6.3 is also looking to improve water quality by reducing pollution, eliminating dumping and minimising release of hazardous chemicals and materials, halving the proportion of untreated wastewater and substantially increasing recycling and safe re-use globally by 2030.

These challenges inform Prof Voua Otomo’s research, which focuses on the drivers of river pollution in the Qwaqwa region, ways to mitigate/remediate their effects, and the development of simple and quick methods to assess water quality. His research, which is part of the UFS 2023 Impact Report, has drawn attention to localised incidences of terrestrial and aquatic contamination linked to sewage sludge management by local wastewater treatment plants.

Using mycofiltration to reclaim the quality of contaminated water

In Qwaqwa, wastewater treatment plants, however, are not the only source of river pollution, as a significant amount of river pollutants emanates directly from the communities that often dispose of their household waste directly into the waterways. This has led to unacceptable levels of pharmaceuticals such as biphenyl-4-ylacetic acid (an anti-inflammatory), efavirenz (an HIV medicine), and carbamazepine (an epilepsy medicine) ending up in rivers.

To attempt to reclaim the quality of contaminated water, ongoing research in Prof Voua Otomo’s laboratory involves the use of ‘mycofiltration’, i.e., the use of fungal mycelia for the purpose of water filtration. This relatively untapped eco-friendly technology is attracting more attention, yet its real merits are only now being established and documented scientifically.

“Various species of fungi have been explored in bioremediation studies, and those belonging to the Pleurotus genus (edible mushrooms) have demonstrated an exceptional ability in the biosorption of contaminants,” says Prof Voua Otomo.

In his field of research, Prof Voua Otomo says snails can be used as bioindicators (i.e., organisms used to assess the health of an environment or ecosystem, particularly by indicating the presence and impact of pollutants or other environmental stressors) or biomonitors (i.e., organisms or a biological systems used to assess the health of an environment, particularly by detecting changes in the levels of pollutants or other harmful substances).

“We designed a mycofilter made of mycelia from the mushroom species Pleurotus ostreatus and filtrated water contaminated with the organic insecticide imidacloprid and the inorganic chemical iron (III). The results showed that mycofiltration could remove up to 94% of iron (III) and 31% of imidacloprid.

“Mycofiltration works through a process called adsorption, which is the process where molecules, ions, or particles from a gas, liquid, or dissolved solid, stick to a surface. This happens when the adsorbate (the substance being adsorbed) attaches to the adsorbent (the surface it adheres to),” Prof Voua Otomo explains.

Mycofiltration viable and affordable for water remediation

This research is the brainchild of Sanele Mnkandla, a final-year PhD student in Prof Voua Otomo’s laboratory. “A few years ago, she suggested looking at mycofiltration as a means to improve the quality of contaminated water. Freshwater snails were the most suitable organisms to help assess the improvement of the water quality after mycofiltration,” explains Prof Voua Otomo.

According to him, they are currently exploring ways to upscale the mycofilter to improve the quality of larger bodies of water, including rivers. The duration of the process depends on the size of the filter, the amount of water to be filtered and the targeted chemicals. Bigger filters, explains Prof Voua Otomo, will filter larger amounts of water over a relatively longer time whereas smaller ones will be saturated quickly. The process could last from minutes to days.

“We have published a technical note on the topic and a proof of concept. We are currently testing this technology using wastewater effluent in the Qwaqwa region. We are also exploring local applications in rainwater harvesting.

“Mycofiltration is certainly a viable and affordable option for water remediation, which can find a wide range of applications in South Africa,” he says.

Watch the video below

Helisoma duryi freshwater snails exposed in non-mycofiltered ferric iron aqueous solution, mycofiltered ferric iron aqueous solution and tap water (control).

Mycofiltration of ferric iron aqueous solution.

Pleurotus ostreatus mycofilter. Thatching straw fully colonised by P. ostreatus mycelia (white).

News Archive

Africa's Black Rhino conservation strategy must change

2017-07-10

The black rhino is on the brink of extinction. The study that was
published in the Nature Scientific Reports reveals that the
species has lost an astonishing 69% of its genetic variation.
Photo: iStock

The conservation strategy of the black rhino in Africa needs to change in order to protect the species from extinction, a group of international researchers has found. The study that was published in the Nature Scientific Reports reveals that the species has lost an astonishing 69% of its genetic variation.

South African researchers took part
The researchers, which included local researchers from the National Zoological Gardens of South Africa (NZG), have highlighted the fact that this means the black rhino is on the brink of extinction. "We have found that there is a decline in genetic diversity, with 44 of 64 genetic lineages no longer existing," said Prof Antoinette Kotze, the Manager of Research and Scientific Services at the Zoo in Pretoria. She is also affiliate Professor in the Department of Genetics at the University of the Free State and has been involved in rhino research in South Africa since the early 2000s.

DNA from museums and the wild
The study compared DNA from specimens in museums around the world, which originated in the different regions of Africa, to the DNA of live wild animals. The DNA was extracted from the skin of museum specimen and from tissue and faecal samples from animals in the wild. The research used the mitochondrial genome.

"The rhino poaching ‘pandemic’
needs to be defeated, because
it puts further strain on the genetic
diversity of the black rhino.”

Ability to adapt
Dr Desire Dalton, one of the collaborators in the paper and a senior researcher at the NZG, said the loss of genetic diversity may compromise the rhinos’ ability to adapt to climate change. The study further underlined that two distinct populations now exists on either side of the Zambezi River. Dr Dalton said these definite populations need to be managed separately in order to conserve their genetic diversity. The study found that although the data suggests that the future is bleak for the black rhinoceros, the researchers did identify populations of priority for conservation, which might offer a better chance of preventing the species from total extinction. However, it stressed that the rhino poaching ‘pandemic’ needs to be defeated, because it puts further strain on the genetic diversity of the black rhino.

Extinct in many African countries
The research report further said that black rhino had been hunted and poached to extinction in many parts of Africa, such as Nigeria, Chad, Cameroon, Sudan, and Ethiopia. These rhino are now only found in five African countries. They are Tanzania, Zimbabwe, Kenya, Namibia, and South Africa, where the majority of the animals can be found.

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