1. Department of Environmental, Water and Earth Sciences, Tshwane University of Technology, Arcadia Campus, Private Bag X680, Pretoria 0001, South Africa
2. Department of Biomedical Technology, Tshwane University of Technology, Arcadia Campus, Pretoria 0001, South Africa
3. Department of Microbiology, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch 7602, South Africa