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16 May 2024 | Story Leonie Bolleurs | Photo supplied
Dr Yolandi Schoeman
Dr Yolandi Schoeman believes the project is directly contributing to the regeneration and conservation of biodiversity, innovating towards creating unique urban biodiversity markets, and creating a thriving natural habitat that supports ecological balance and resilience.

Tim Briercliffe, Secretary General of the International Association of Horticultural Producers (AIPH), recently congratulated the City of Tshwane for the work done on urban greening and nature-based solutions that resulted in its entry: ‘Republic of South Africa City of Tshwane Pretoria East Urban Biosphere Reserve’ being selected as one of 21 finalists in the Living Green for Biodiversity category of the AIPH World Green City Awards 2024.

The list of finalists comprises the three highest-scoring entries in each of the seven categories. The Tshwane project was entered in the Living Green for Biodiversity and Urban Ecosystem Restoration category as well as the Living Green for Urban Infrastructure and Liveability category.

Dr Yolandi Schoeman, Postdoctoral Fellow/Researcher in Ecological Engineering in the centres for Mineral Biogeochemistry and Environmental Management and the Ecological Engineering Institute of Africa at the University of the Free State (UFS), played a critical role in conceptualising and driving the bio-intelligent approach that is integral to the Tshwane SA Biosphere Reserve project.

She states that being part of a project recognised as a finalist for such a prestigious global award is profoundly gratifying. “It underscores the importance and urgency of our work in ecological engineering and biodiversity conservation, validating our efforts to create resilient urban ecosystems that can inspire similar initiatives globally.”

Enhancing urban sustainability

According to her, it is one of the university’s flagship projects in Gauteng. “Our team was pivotal in developing the methodological framework that facilitated the integration of ecological, economic, social, and technological dimensions to effectively address climate change, biodiversity loss, disconnections in coupled human and natural systems, and enhance urban sustainability.”

Dr Schoeman says the project was initiated in the early stages of their investigations into sustainable urban development, with notable developments in 2023, as highlighted during the City of Tshwane Climate Change and Research Conference. She indicates that the project is continuing, with phases that include various baseline research activities, active ecosystem regeneration, continuous monitoring, roll-out of a unique biodiversity citizen science approach, integrated and inclusive stakeholder involvement, creating a unique urban biodiversity market, awareness and capacity building, and moving towards formally applying to the International Union for Conservation of Nature (IUCN) for the formal recognition of the urban biosphere region within the greater Pretoria East area.

She remarks that her inspiration to engage in this project stemmed from a commitment to address the multifaceted challenges posed by climate change and biodiversity loss, particularly in urban settings. “The most remarkable aspect of the project is its innovative approach to integrating urban development with ecological engineering, fostering a sustainable coexistence between humans and nature that serves as a model for cities worldwide,” she says.

She is excited about the impact of the work that has been done. Not only is the project directly contributing to the regeneration and conservation of biodiversity, creating a thriving natural habitat that supports ecological balance and resilience, but it is also impacting the greater Tshwane community. Dr Schoeman believes that the project significantly enhances community engagement and participation, which in turn fosters greater awareness and responsibility towards sustainable living practices.

Crafting practical, impactful solutions

Besides her instrumental role in making an impact, Dr Schoeman also enjoyed the project, particularly the opportunity to collaborate with a diverse group of stakeholders, including local communities, government bodies, and fellow researchers. “This multidisciplinary collaboration has not only enriched the project but has also been instrumental in crafting practical, impactful solutions tailored to the specific needs and characteristics of Tshwane,” she comments.

As a finalist in the Living Green for Biodiversity category of the AIPH World Green City Awards 2024, the city of Tshwane will receive a Highly Commended certificate at an awards ceremony in September in Utrecht, the Netherlands, and will ultimately have the opportunity to win the title of Grand Winner of the 2024 edition of the AIPH World Green City Awards.

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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