Discover how confectionery waste is converted into bioethanol, biobutanol, and biogas, promoting sustainability and reducing environmental pollution.
A University of Cape Town (UCT) doctoral study in Chemical Engineering has found that confectionery waste has strong potential as a feedstock for bioenergy production while supporting waste reduction and resource efficiency.
The PhD study by Dr Carol Ngwenya investigated whether carbohydrate-rich confectionery waste can be repurposed for renewable bioenergy production instead of being disposed of in a landfill.
She evaluated the feasibility of producing bioethanol, biobutanol and biogas from confectionery waste using different microbial systems. The findings demonstrated that these waste streams can be successfully converted into bioenergy, with process optimisation and microbial acclimatisation improving substrate utilisation and energy production.
Titled: “The feasibility of renewable bioenergy production from carbohydrate-rich waste streams: confectionery waste as a case study”, this research was motivated by the urgent need to develop a sustainable bio-based economy to support South Africa’s social and economic growth.
Renewable energy solutions
“National science and innovation strategies, such as South Africa’s Waste RDI Roadmap and the Integrated Resource Plan, emphasise the importance of using waste materials as renewable resources rather than disposing of them in landfill,” said Dr Ngwenya.
“Carbohydrate-rich waste streams generated by food processing industries, particularly confectionery manufacturing, are often disposed of as solid waste despite their high energy potential. This project was therefore driven by the opportunity to redirect these waste streams into biological processes for renewable bioenergy production,” she said.
The study provides detailed insights into microbial systems, process optimisation and the comparative feasibility of different bioenergy pathways from carbohydrate-rich waste streams. By evaluating different carbon sources and identifying suitable microbial routes for energy recovery, the work offers practical guidance on selecting appropriate waste-to-energy technologies.
Advancing waste-to-energy
Ngwenya said entrepreneurs and innovators in the waste-to-energy sector can use these insights to support the development and implementation of sustainable bioenergy solutions in South Africa.
Converting confectionery waste into bioenergy can reduce environmental pollution, improve waste management practices and contribute to renewable energy generation. In South Africa, waste-to-energy technologies also have the potential to diversify energy supply while supporting the transition toward a more sustainable and resource-efficient economy.
An important aspect of the study was the comparative assessment of different bioenergy conversion routes using the same waste substrate. By evaluating bioethanol, biobutanol and biogas production from confectionery waste, the research provided insight into how different microbial systems and conversion technologies perform depending on the composition of the waste stream.
