Potentials of Bacteria and Fungi Isolated from Oil-polluted Soil in Biodegradation of Perfluorononanoic Acid

The objective of this paper is to investigate the potential of bacteria and fungi isolated from oil-polluted soil in the biodegradation of perfluorononanoic acid (PFNA) using appropriate standard techniques. Data obtained show that significant quantities of the physical and chemical characteristics needed for microbial growth were present in the soil. The soil samples had the highest mean total heterotrophic bacterial and fungal counts of 10.9×105 cfu/g and 7.18×105 sfu/g, respectively. The bacteria identified were Bacillus cereus, Acinetobacter spp., Klebsiella spp., Pseudomonas putida, Serratia marcescens, Staphylococcus aureus, Micrococcus spp., Vibrio spp. and Burkholderia species. The fungal isolates identified were Penicillium, Rhodotorula, yeasts, Aspergillus niger, Trichoderma, and Fusarium species. Among the bacterial isolates, Pseudomonas putida had the highest occurrence of 22.6%, while Micrococcus sp. and Vibrio sp. were the least with equal occurrence of 6.5%. For fungal isolates, Aspergillus niger had the highest occurrence of 28.6%, while Rhodotorula sp. and yeasts were the least with equal occurrence of 10.7%. Bacillus cereus and Aspergillus niger had the highest tolerance indices at all concentrations of PFNA (100, 150, and 200 ppm). The biodegradation of PFNA by Pseudomonas putida and Aspergillus niger revealed that Bacillus cereus grew at all concentrations at 24 hours, 48 hours, and reduced at 168 hours, while Aspergillus niger had the highest plate count at 100 ppm, followed by 150 ppm, after degradation. Hence, these findings indicate that the species isolated can resist high amounts of toxic chemicals and can withstand any harsh environment, hence their ability to serve as potential agents for the bioremediation of PFNA and other PFAS compounds at a cheap cost.