Bioaugmentation of Native Fungi, an Efficient Strategy for the Bioremediation of an Aged Industrially Polluted Soil With Heavy Hydrocarbons

Abstract

The concurrence of structurally complex petroleum-associated contaminants at relatively high concentrations, with diverse climatic conditions and textural soil characteristics, hinders conventional bioremediation processes. Recalcitrant compounds such as high molecular weight polycyclic aromatic hydrocarbons (HMW-PAHs) and heavy alkanes commonly remain after standard soil bioremediation at concentrations above regulatory limits. The present study assessed the potential of native fungal bioaugmentation as a strategy to promote the bioremediation of an aged industrially polluted soil enriched with heavy hydrocarbon fractions. Microcosms assays were performed by means of biostimulation and bioaugmentation, by inoculating a defined consortium of six potentially hydrocarbonoclastic fungi belonging to the genera Penicillium, Ulocladium, Aspergillus, and Fusarium, which were isolated previously from the polluted soil. The biodegradation performance of fungal bioaugmentation was compared with soil biostimulation (water and nutrient addition) and with untreated soil as a control. Fungal bioaugmentation resulted in a higher biodegradation of total petroleum hydrocarbons (TPH) and of HMW-PAHs than with biostimulation. TPH (C14-C35) decreased by a 39.90 ± 1.99% in bioaugmented microcosms vs. a 24.17 ± 1.31% in biostimulated microcosms. As for the effect of fungal bioaugmentation on HMW-PAHs, the 5-ringed benzo(a)fluoranthene and benzo(a)pyrene were reduced by a 36% and 46%, respectively, while the 6-ringed benzoperylene decreased by a 28%, after 120 days of treatment. Biostimulated microcosm exhibited a significantly lower reduction of 5- and 6-ringed PAHs (8% and 5% respectively). Higher TPH and HMW-PAHs biodegradation levels in bioaugmented microcosms were also associated to a significant decrease in acute ecotoxicity (EC50) by Vibrio fischeri bioluminiscence inhibition assays. Molecular profiling and counting of viable hydrocarbon-degrading bacteria from soil microcosms revealed that fungal bioaugmentation promoted the growth of autochthonous active hydrocarbon-degrading bacteria. The implementation of such an approach to enhance hydrocarbon biodegradation should be considered as a novel bioremediation strategy for the treatment of the most recalcitrant and highly genotoxic hydrocarbons in aged industrially polluted soils.

Efficiency of Penicillium canescens in Dissipating PAH in Industrial Aged Contaminated Soil Microcosms and Its Impact on Soil Organic Matter and Ecotoxicity

“…This result would suggest that the presence of P. canescens in BA4 provides better high-Log Kow i.e., better HMW PAH dissipation than with endogenous microflora alone. Such a dissipation of high-Log Kow PAH in microcosms by filamentous fungi has been reported with other fungi [5,17,31]. However, PAH dissipation was approximately 3.6 greater for BA4 in comparison with NA.…”

“…Their dissipation at a rate higher than 18% in BA4 most likely indicates that P. canescens has a high capacity to degrade hydrophobic aromatic molecules. Such a significantly lower reduction of five-and six-ringed PAH is very rarely obtained in similar studies conducted in aged soils [5]. The selected P. canescens strain was isolated in a previous study from a former bus depot in northern France and was selected as the most efficient strain in BaP degradation (44.2%) in a mineral medium [17].…”

“…However, in recent years, soft chemical oxidation methods, i.e., Fenton-like oxidation, which are more respectful of the soil integrity, have also been developed [4]. Among biological ones, bioremediation by fungi is one of the most cost-effective and soil-friendly [5]. Fungi, representing the dominant living biomass in soils, have an important advantage over bacteria with their mycelial network able to prospect a larger surface of soil.…”

Comparison of the Strength of Biodegradation of Pyrene between Symbiont Bacteria of Marine Sponges and Bacteria Isolated from Seawater

“…The results of this study are expected to be developed to screen for other types of bacteria from various sources that can biodegrade hydrocarbon components, especially PAHs [94,95]. The achievements of this research also open up opportunities for using these bacteria in the bioremediation of other types of pollutants, such as pesticide residues, heavy metals and microplastics, so that the dream of formulating crystalline carbonoclastic bacteria can be realized [12,21,64]. This hope is a form of environmental protection against the threat of contamination by toxic components.…”

“…Sphingobacterium group of bacteria is a genus that belongs to the Sphingobacteriaceae family, containing high concentrations of sphingophospholipids [11,63]. Sphingobacterium is a group of bacteria isolated from several habitat sources, one of which can be obtained from seawater [64]. Both groups of bacteria can biodegrade aromatic hydrocarbon components.…”