Optimization of the South African indigenous fungal growth for the degradation of diclofenac sodium from water

Abstract

Background and objectivesThe occurrence of endocrine-disrupting compounds (EDCs), pharmaceuticals and personal care products (PPCPs) or active pharmaceutical ingredients (APIs) and their risk assessment in the environment over a decade have become a real concern in various existing water resources. Microbial bioremediation of organic pollutants in wastewater is a key process in both natural and engineered systems. This study aimed to the use of green technology with South African indigenous fungi for the removal of diclofenac from water, which is an environmentally friendly process applied to manage water quality at large.\n\nMethodThe fungal growth was optimised in flasks, then the aerated and stationary batch flasks were run for 14 d and samples taken once daily in order to carry out the fungal removal efficiency of the most popular and anti-analgesic anti-inflammatory drug (NSAID) diclofenac sodium (DCF) from water. The five isolate South African indigenous fungal strains (ISAIFS) T. longibrachiatum, T. polyzona, A. niger, M. circinelloides and R. microsporus were then found to have a optimum growth in low nitrogen medium (LN-m) at temperature range of between 26.5{degrees}C to 31.5 {degrees}C and pH around 3 to 4.5.\n\nResultsAspergillus niger gave better growth and seemed thermotolerence than others. Glucose supply as well as physicochemical parameters such as pH and temperature have shown to have play a vital role on fungal growth in suspension liquid media. The best DCF degradation result obtained was 95% by R. microsporus in aerated batch flasks after 7 d followed by A. niger with 80% of DCF removal, while the only one white-rot fungi (WRF) of that isolate fungal group, T. polyzona did not give the best DCF elimination as expected for the same period.\n\nConclusionFinally, the effectiveness of DCF elimination by each isolate South African indigenous fungal strain (ISAIFS) was found to be better than some traditional methods used in wastewater treatment plants, including: coagulation-flocculation, nitrifying and denitrifying and sewage treatment. These fungal species especially R. microsporus, A. niger and M. circinelloides can be used for the degradation of emerging pollutant in wastewater treatment plants.