Removal and biodegradation of different petroleum hydrocarbons using the filamentous fungus Aspergillus sp. RFC‐1

Abstract

Petroleum pollution inevitably occurs at any stage of oil production and exerts a negative impact on the environment. Some microorganisms can degrade petroleum hydrocarbons (PHs). Polluted sludge of Rumaila oil field was use to isolate the highly efficient hydrocarbon‐degrading fungal strain. Aspergillus sp. RFC‐1 was obtained and its degradation ability for petroleum hydrocarbons was evaluated through surface adsorption, cell uptake, hydrophobicity, surface tension, biosurfactant production, and emulsification activity. In addition, the degradation mechanism was investigated. The results indicated the strain RFC‐1 showed high removal activity for PHs, including biodegradation, adsorption, and emulsifiability. On the day 7 of incubation, the removal efficiencies of crude oil, naphthalene (NAP), phenanthrene (PHE), and pyrene (PYR) reached 60.3%, 97.4%, 84.9%, and 90.7%, respectively. Biodegradation efficiencies of crude oil, NAP, PHE, and PYR were 51.8%, 84.6%, 50.3%, and 55.1%, respectively. Surface adsorption and cell absorption by live mycelial pellets followed a decreasing order: PYR ≥ PHE > NAP > crude oil. Adsorption by heat‐killed mycelial pellets increased within 40 and 10 min for crude oil and PAHs, respectively, and remained constant thereafter. Effects of cell surface hydrophobicity, surface tension, and emulsification index were discussed. Intra‐ and extracellular enzymes of strain RFC‐1 played important roles in PHs degradation. The strain RFC‐1 is a prospective strain for removing PHs from aqueous environments.

Factors affecting polycyclic aromatic hydrocarbon biodegradation by Aspergillus flavus

“…The ability of this species to produce more than one type of degradative enzyme in high quantities may increase its potential to degrade PAH compounds (Barnes et al, 2018; Mohsenzadeh et al, 2012). These results are consistent with those of other studies in which fungi especially the genus Aspergillus has a great degradation ability for hydrocarbons (Al‐Hawash et al, 2018; Ponnapalli et al, 2018; Ye et al, 2011).…”

“…corresponding to 92.41% degradation (Figure 3). This finding is consistent with that of several studies (Al‐Hawash et al, 2018; Govarthanan et al, 2017; Hamzah et al, 2012), which reported that the optimum temperature for fungal growth during the oil degradation processes was 30°C. This may be because of an increase in fungal growth, which potentially improved energy efficiency in the system by facilitating contact between the cell surfaces and the energy source.…”

“…The two species with the highest potential among the fungal isolates, A. flavus and A. fumigatus , were selected to test their ability to degrade PAHs as single isolates. These two fungi belong to the genus Aspergillus ; many species of this genus have been previously isolated and have demonstrated their ability as oil degraders (Al‐Hawash et al, 2018; Al‐Nasrawi, 2012; Mittal & Singh, 2008; Ponnapalli, Sura, Sudhakar, Govindarajalu, & Sijwali, 2018). In the present study, a significant amount of total PAHs was degraded after 15 days of incubation compared with the control treatment.…”

“…Previous research have focused on natural processes such as biodegradation, which uses a microbial consortium, to degrade PAHs in the environment (Hassanshahian, Emtiazi, & Cappello, 2012). With respect to biodegradation, fungi possess certain advantages over bacteria, owing to the nature of their growth patterns and their resistance to PAHs, as demonstrated by several studies (Al‐Hawash, Zhang, & Ma, 2018; Li et al, 2008; Mauti, Onguso, Kowanga, & Mbak, 2016; Marchand et al, 2017). Filamentous fungi have been readily isolated from oil‐contaminated sites and have demonstrated the ability to degrade PAHs.…”

Bioremediation of Crude Oil by Rhizosphere Fungal Isolates in the Presence of Silver Nanoparticles

“…The first mechanism promotes the emulsification of hydrophobic compounds to mycelial pellet structures. The second mechanism induces high cell surface hydrophobicity, thus increasing the direct physical contact between cells and poor water-soluble substrates [38,39].…”