Heliyon. 2022 Jul 2;8(7):e09854. doi: 10.1016/j.heliyon.2022.e09854. eCollection 2022 Jul.
Myco-remediation of heavy metals using indigenous fungi of different petroleum refining areas in Egypt was applied. Among the physicochemical parameters determined in these refineries effluents, the highest levels of heavy metals were recorded for the most toxic heavy metals Fe3+ and Co2+. The fungal isolates under the isolation codes AHM69 and AHM96 isolated from the mycobiome of Mostorod and Tanta refineries, respectively showed the best bioremoval efficiency toward heavy metals from the real wastewater mixture and polycyclic aromatic hydrocarbons from aqueous solutions. Based on phenotypic and genotypic analysis they were identified as Aspergillus sp. AHM69 and Penicillium sp. AHM96. The optimum conditions for the best bioremoval of Fe3+ and Co2+ from aqueous solutions by Aspergillus sp. AHM69 were live biomass, temperature 45-55 °C, pH 4.5-5.0, contact time 180 min, metal concentration equal to 1000 and 400 mg/L of Fe3+ and Co2+ with live fungal biomass dose of 0.5% and 0.4% with Fe3+ and Co2+, respectively. Concerning to the biomass of Penicillium sp. AHM96, the optimum operation conditions for the best removal of Fe3+ and Co2+ were 45 °C, pH 5.0 and 400 mg/L of Fe3+ with 1.0% biosorbent dosage or 1000 mg/L of Co2+ with 0.5% biosorbent dosage for 180 min as process time. Furthermore, FTIR analysis showed masking, shifting, creating and absenting of different functional groups in the fungal biomass surface of AHM96 and AHM69 strains in the presence of Fe3+ and Co2+ compared to unloaded biomasses. Microscopy with Energy Dispersive X-ray analysis (SEM-EDX) indicated that the removal of Fe3+ and Co2+ by fungi AHM69 and AHM96 was via biosorption and bioaccumulation on the biomass surface. Our results suggested that in the near future, fungal treatment is likely to outperform and replace other chemical and biological treatments in industrial wastewater treatment for oil refining.