Plant-Soil-Microbiota Combination for the Removal of Total Petroleum Hydrocarbons (TPH): An In-Field Experiment

Abstract

The contamination of soil with total petroleum hydrocarbons (TPH) may result in dramatic consequences and needs great attention, as soil rehabilitation would need more effort from a sustainability perspective. However, there is still no known general method since the remediation technology is strictly site-specific. Adaptive biological system dynamics can play a key role in understanding and addressing the potential of situ-specific biological combinations for soil pollutants removal. The potential worst-case of TPH contamination reflects soil affected by heavy industrial activities, such as oil refineries. Therefore, the experimental trial was conducted on a 2,000 m2 area from a contaminated site located in northern Italy. We evaluated the remediation potential over time (270 days) assessing (i) the phytoremediation efficiency of two species of Poaceae (Festuca arundinacea Schreb. and Dactylis glomerata L.) and two species of Fabaceae (Medicago sativa L. and Lotus corniculatus L.) and (ii) the role of the indigenous bacteria flora and endo-mycorrhizae consortium addition in plant growth promotion. We also induced resistance to contamination stress in a field experiment. Thirty-three indigenous bacteria selected from the contaminated soils showed marked plant growth promotion. Moreover, functional metagenomics confirmed the metabolic capability of hydrocarbon-degrading microorganisms living in the polluted soil. Our data showed that soil enzymatic activities increased with hydrocarbon degradation rate after 60 days. Both Poaceae and Fabaceae resulted in remarkable remediation potential. Stress markers and antioxidant activity indicated that the selected plant species generally need some time to adapt to TPH stress. In conclusion, our evaluation implied both the rhizosphere effects and functional features of the plant and suggested that plants should (i) have marked tolerance to specific contaminants, (ii) be characterized by an extensive root system, and (iii) be susceptible to arbuscular mycorrhizal fungi (AMF) infection.

Biodiversity and biocatalyst activity of culturable hydrocarbonoclastic fungi isolated from Marac–Moruga mud volcano in South Trinidad

“…Hydrocarbonoclastic strains produce mono- and di- oxygenases that aid in initial oil degradation steps 92 , 93 and support fungal growth on recalcitrant substrates 16 . As the second largest class of enzymes used in biotechnology, oxidoreductases have been linked to acceleration of degradation of hydrocarbons and there is a correlation between enzymatic redox activities in soil as an early indicator of oil degradation 94 . In this study, hydroxylase activity was recorded for fungal strains when ABTS as a non-phenolic substrate and gallic acid, catechol, hydroquinone, resorcinol, orcinol, tannic acid and methylene blue phenolic substrates were used.…”

Root exudate glycine synergistically promotes phytoremediation of petroleum-contaminated soil

“…Traditional physical-chemical methods including excavation, desorption, thermal destruction, soil washing, soil flushing, stabilization, soil vapor extraction, and many others. Although these methods are fast and effective, they have some limitations, such as high cost, high labor intensity and they tend to compromise the environmental matrices (Zuzolo et al, 2021). Bioremediation for petroleum contaminated soil mainly include phytoremediation, microbial remediation, and microbial-plant combined remediation.…”

Microbiological Study in Petrol-Spiked Soil

“…In our study, cocksfoot proved effective in petrol degradation, and this effect was mainly due to its stimulating impact on soil microorganisms. The microbiological degradation of petroleum hydrocarbons in the soil is a natural process, owing to which organic pollutants can be mineralized by autochthonous microorganisms [ 41 , 84 ]. The cultivation of cocksfoot enhanced their activities as a result of the stimulating effect of root secretions on their development [ 42 , 60 ].…”