Dr Senzo Mkhize earned his PhD in Biochemistry for a dissertation titled: Bioaccumulation of Heavy Metals together with Medicinal Properties of Pleurotus spp Cultivated on Agro-Industrial Substrates Supplemented with Wheat Bran and Maize Flour.

He was supervised by Dr Ofentse Pooe and Professor Mthokozisi Simelane, and has so far published five research articles and one book chapter from his PhD project.

Mkhize’s research demonstrated that the cultivation of Pleurotus ostreatus (oyster mushrooms) with wheat bran or maize flour supplements significantly improved their yield as well as their medicinal properties.

His work demonstrated the mushroom’s capacity to absorb heavy metals across different substrates and its application in synthesising zinc oxide nanoparticles with potent antioxidant and antimicrobial potential.

Having always been fascinated and inspired by science, Mkhize is the first member of his family to obtain a PhD. ‘The desire to improve my family’s situation, to set an example as the first “Dr” in my village and encourage the young people to value education above all else regardless of financial status, and to use research to impact society positively has inspired and driven me,’ he said.

He chose UKZN because of its reputation for producing skilled, internationally-recognised postgraduates and paid tribute to his supervisor, Pooe, for being ‘a young doctor with high research ethics and skills’ who taught him how to undertake new, novel and original research independently.

‘My PhD research demonstrated that mushroom cultivation with wheat bran or maize flour supplements significantly improves yield as well as the medicinal properties of Pleurotus ostreatus mushrooms,’ said Mkhize. ‘My project demonstrated the mushroom’s capacity to absorb heavy metals across various agro-industrial waste substrates, and its application in synthesising zinc oxide nanoparticles with potent antioxidant and antimicrobial potential. The findings highlighted the potential of P. ostreatus mushroom in synthesising nanomaterials through a cheap and environmentally friendly method (green synthesis).’

Mkhize’s search for an alternate source of compounds and nanomaterials with medical properties was prompted by an observable rise in non-communicable diseases affecting communities and hospitals, as well as a rise in hospital-acquired infections caused by multidrug resistant microorganisms.

‘Mushrooms have the advantage of being easily cultivated at low cost using locally neglected waste substrates (sugar cane leaves and bagasse),’ said Mkhize. ‘Moreover, even a slight change in growing substrates can alter the amount and type of bioactive compounds found in mushrooms, resulting in a completely new set of molecules with therapeutic properties.

‘Hence, my study focused on the optimisation of mushroom-growing substrates through the addition of wheat bran and maize flour supplements in order to promote the mushroom’s secondary metabolite with therapeutic properties.’

He also evaluated the ability of oyster mushrooms to accumulate heavy metals from locally available growing substrates, to see if they could be deployed in contaminated environments as bioremediators.

A fascination with nanotechnology and its application in engineering and biomedical science led him to advocate further for the use of mushrooms as a capping agent for the synthesis of nanoparticles, as being cost-effective, non-toxic and eco-friendly.

‘Mushroom-derived nanoparticles are known to have high stability, longer shelf life, water-solubility, and good dispersion properties,’ said Mkhize. ‘This technology of synthesising nanoparticles using mushrooms is very promising for the synthesis of non-toxic, eco-friendly and mostly stable nanomaterials. We managed to synthesise stable and biocompatible ZnO nanoparticles, which can be an efficient antimicrobial and potential anti-cancer agent, using a fast, safe, cost-effective and eco-friendly green method.

‘Finally, the environment is increasingly exposed to heavy metals which pose serious health issues to humans; thus finding alternative ways to eradicate such toxins could be very useful. Since mushrooms produces enzymes which can eradicate the recalcitrant compounds within the environment, they can therefore be used as bioremediators of the environment.’

With his PhD behind him, Mkhize is aiming for a postdoctoral research position and a future career in academia. ‘All things considered, I am looking forward to improving my family’s circumstances since I strongly believe that charity begins at home,’ he said. ‘My great motivation came from them and they have always believed in me.’

Words: Sally Frost

Photograph: Sethu Dlamini