An in-depth look at how enzymes benefit the bio-economy

Vice-Chancellor Dr Sizwe Mabizela with Professor Brett Pletschke
Vice-Chancellor Dr Sizwe Mabizela with Professor Brett Pletschke

By Lindeka Namba, School of Journalism and Media Studies student


As the recipient of the 2018 Vice Chancellor’s Senior Distinguished Research Award, Professor Brett Pletschke presented a lecture on his research topic and findings on 14 August in the Eden Grove Blue lecture theatre.

The Eden Grove lecture theatre was filled with academics, Rhodes University students and members of the general public who were ready to listen to what Prof Pletschke had to say about enzyme biotechnology, bioproducts and the bio-economy.

Prof Pletschke explained that moving from historically fossil fuel driven economies to bio-economies has the potential to cause a shift in power and in flatter more equitable economies. Drawing on the concept of the rich global north versus the poor global south, Prof Pletschke said, “We can use the bio-economy as a way for the global south to catch up to the global north.” His message was a simple one from the beginning: that enzymes and enzyme technology are remarkable agents that can drive the bio-economy.

In his lecture, Prof Pletschke highlighted the latest developments in using enzyme biotechnology for the development of suitable bio-products for serving the national and international bio-economy agenda.

He touched on three programmes that are currently taking place in his research group, which all highlighted the ways in which enzyme biotechnology benefits bio-economy and society.

The first of these programmes is improving the competitiveness of the bio-economy by breaking down spent coffee grounds and aloe plant biomass into value added products such as prebiotic manno-oligosaccharides (MOS) (sugars). He spoke about how prebiotics, which are non-digestible food oligosaccharides, stimulate beneficial bacteria in the gut and kill unwanted bacteria. “MOS allows the good bacteria in our guts to flourish and out-compete the bad bacteria,” he explained. He pointed out that they are fermented in the colon by probiotic bacteria, which is obviously very important.

The second research project concerns the creation of enzyme formulations for use as food additives to break down non-starch polysaccharides in animal feed grains leading to increased nutrient availability and accelerated digestion. This, in turn, leads to improved animal growth and performance. As human meat consumption continues to be on the rise, the pressure continues to mount on animal feed production to be better and to produce greater results to meet the rising demand.

The problem which arises is that most local subsistence farmers use agro-industrial wastes as feed, such as corn (mealies), soy bean meal and wheat bagasse, all of which contain non-starch polysaccharides (NSPs). This means that nutrients such as starch and protein are encapsulated and cannot easily be released for the nourishment of the animals while they feed. Xylanases are then used synergistically to degrade the NSPs and allows the necessary nutrients to be released and contribute to the accelerated digestion process for animals.

The third research project involves the use of seaweed fucoidans to combat diabetes, obesity and cancer. Fucoidan from Ecklonia maxima and Macrocystis pyrifera are commonly found in brown seaweeds and are powerful inhibitors of diabetes and obesity-related enzymes and the breast cancer cell line HCC70. Prof Pletschke brought to light some of the staggering world statistics which highlighted 36.9 million people living with HIV/AIDS; 100 million people with cancer; more than 422 million people with diabetes; and 2.1 billion people who are considered to be obese. “Fucoidans are attractive as potential anti-diabetic/anti-obesity agents,” he said.

Prof Pletschke concluded by recalling that our enzymes or a study of these agents benefit the bio-economy and society through second generation (2G) biofuel production; nutrition, nutriceuticals, human prebiotics and animal feeds; and the treatment of diabetes, obesity and cancer.

In his closing remarks, Prof Pletschke acknowledged some of the people who have played an instrumental role in his research efforts, including Vice-Chancellor of Rhodes University, Dr Sizwe Mabizela; DVC of Research and Innovation, Dr Peter Clayton - and the Research Award Committee; as well as DVC of Academic and Student Affairs, Dr Mabokang Monnapula-Mapesela; and his colleagues at the University. Acknowledgements were also extended to the students who are part of the research and to his family for their constant support.