Women's Month 2023: Dr Lethiwe Debra Mthembu

August is Women’s Month, and this year the National Research Foundation (NRF) is celebrating the remarkable contributions that have been made by women researchers for the betterment of humanity. We thank all participants for sharing their stories with us.

Dr Lethiwe Debra Mthembu is a Postdoctoral Fellow in Chemistry at the Durban University of Technology (DUT) and a part-time Lecturer at the Mangosuthu University of Technology (MUT). She received funding from the NRF for her postgraduate and postdoctoral studies.

What impact did the NRF have on your studies/career?

I first received NRF funding for my BTech at MUT which was quite helpful because I was unemployed and my mother is a pensioner, making it hard for me to pay tuition expenses. I was supported by the NRF for my Master’s, which linked to my supervisor’s NRF grant. I obtained Doctoral Innovation funding for my PhD (2016 – 2018) and was awarded NRF Scarce Skills postdoctoral funding.

Because of NRF, I was able to focus on my studies as a full-time student throughout my postgraduate qualifications.

What has been your study/career journey?

My high school chemistry teacher, Miss Fundisiwe Gumede, instilled in me a love for the subject since she was so enthusiastic about teaching Physical Chemistry. When I visited MUT, I noticed the Analytical Chemistry course which included a variety of chemistry, and I thought it would be fascinating. I registered for the Analytical Chemistry Diploma. I later completed a National Diploma and a BTech at MUT – it was quite difficult, but I concentrated only on my studies.

After graduating from BTech, my project supervisor, Dr Njabulo Gumede, who was pursuing his PhD at the time, motivated me to pursue Master’s and PhD studies. I then went to DUT to enrol for a Master’s degree under the supervision of Prof Nirmala Deenadayalu and co-supervisor Dr Prashant Reddy. For my Master’s, I went to India for one month and Germany for two months for research visits with NRF funding from my supervisor. During those research visits we published papers and I fell more in love with being a scientist.

I also obtained a Doctoral degree at DUT under the same supervisor but with a different co-supervisor, Prof. David Lokhat. In the second year of my PhD, I received the L’Oréal-UNESCO Sub-Saharan Africa Regional Fellowship for Women in Science, which is my best achievement to date. In 2019, I received the Gagasi FM SHERO Award in the Science and Technology Category, and in 2022, I received the SACI Sasol Postgraduate Award for my PhD. Last year, I started my postdoctoral position at DUT, and I was awarded NRF Postdoctoral Scarce Skills funding.

In addition, I work as a part-time Lecturer at MUT. I’ve been a tutor, lab demonstrator, and lecture assistant. Chemistry is currently my favourite since it provides solutions to the world’s socioeconomic problems.

What is your research focus on/what is your area of expertise?

My research focus area is biomass processing. I investigate environmentally friendly methods to produce products from sugarcane bagasse. Sugarcane bagasse is a type of biomass that is produced after extracting juice from sugarcane.

Why is your research/work important?

The depletion of fossil fuels is a problem that we are currently facing, as most chemicals are produced from fossil fuels. Hence, biomass is investigated as an alternative in the production of various chemicals. Biomass in a renewable resource is usually made up of three major components: cellulose (43.8 %), hemicellulose (27.5 %), and lignin (5.0 %) (Schmidt et al. 2017). There are different types of biomass such as wheat straw, corn, water hyacinth, wood, pulp slurry, rice husk, sorghum grain, tobacco chops, olive tree pruning, poplar sawdust, paper sludge, and sugarcane bagasse (Rackemann and Doherty. 2011; Himmel et al. 2007; Abdulkhani et al. 2013).

In my research, I use sugarcane bagasse because I live in KwaZulu-Natal where there is an excess of sugarcane bagasse. Sugarcane bagasse is a solid residue that is left after the extraction of juice from sugarcane to make sugar.

Also, around the world, there is an excess of sugarcane bagasse of approximately 500 million wet tons (~250 million dry tons) produced annually (Chambon et al. 2018). The NREL discovered 14 platform chemicals that can be produced from biomass. The 14 platform chemicals are furfural, xylitol, glucaric acid, succinic acid, itaconic acid, aspartic acid, glycerol, 3-Hydroxypropionic acid, 3-Hydroxybutyrolactone, 5-HMF, sorbital, 2.5-furandicarboxylic acid, levulinic acid, itaconic acid, and glutamic acid (Werpy and Petersen, 2004).

Another challenge in the manufacturing of chemicals is high greenhouse gas emission which leads to global warming and climate change, consequently, there is more research interest in catalysts and solvents that releases negligible vapour. Hence, I am investigating an efficient and environmental method to produce chemicals from biomass. I aim to start a biorefinery company in South Africa that can employ many unemployed graduates, thus solving another problem which is a high rate of unemployment.

There is still a long way to go to truly achieve equity and a sense of belonging for women, be it within the research community or society in general. How do you envision yourself contributing to this space?

True, however, in my field there are already many women. 

Many young people and adults are unaware of PhDs, so while I am a “doctor”, some people believe I am a medical doctor. I must explain the different types of doctors. When young people in my neighbourhood and church, and social media friends and classmates, see my accomplishments, they are inspired.

I contribute by motivating others and, as a lecturer, I make it a point to inform my students about my experience to encourage them and educate them on how to succeed as researchers. In addition, I supervise advanced students, Master’s and PhD students, the majority of whom are women.

What advice do you have for girls who are interested in STEM-related careers?

Girls should concentrate on their academics and excel since this is how they will be able to obtain funding and avoid having to worry about fees and other responsibilities. Choose a STEM-related profession that you are passionate about because studying is extremely difficult and requires a strong desire to succeed. Respect is essential in every profession, so they must respect everyone.

Given that I attended a township school with no laboratory, I am proud of what I have accomplished. I wish females could be educated to speak in public from a young age because, as researchers, you must present at local and international conferences. I would also like institutions to remind Diploma students that Master’s and PhD programs are mostly about writing so that they may prioritise their writing abilities early on.

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