Fire Phoenix mediated bioremediation of high-PAHs contaminated soil enhanced by graphene oxide application

Soil polluted by polycyclic aromatic hydrocarbons (PAHs) is a serious problem in the world. Phytoremediation is an inexpensive and environmentally benign method for minimizing PAHs from contaminated soils. Nanomaterials have been reported to enhance phytoremediation efficiency. In the present study, Fire Phoenix were planted in low (105.00 ± 18.45 mg kg⁻¹) and high (154.55 ± 20.78 mg kg⁻¹) PAH-contaminated soils supplemented with 0, 300, 400, 500, and 600 mg kg⁻¹ graphene oxide (GO), respectively. After 0, 60, 120, and 150 days of plant growth, plant canopy heights, biomass, removal rates of PAHs, rhizosphere microbial community composition as well as the expression of functional genes of microbial organisms were investigated. Results showed that GO at a given concentration increased biomass accumulation of Fire Phoenix grown in low- or high PAHs contaminated soils. The removal rate of ∑6PAH, especially high-ring PAHs, from high-PAH-contaminated soil was high by GO treatment. Compared with the control treatment, GO application at 500 mg kg⁻¹ resulted in 21.35 %, 22.74 %, and 6.17 % of ∑6PAH removed from high-PAH-contaminated soil after 60, 120, and 150 days of plant growth, respectively. The soil microbial analysis showed that the abundance of Pseudomonas, Sulfuritalea, KCM-B-112, and Mycobacterium significantly changed in soils. Spearman correlation analysis showed that Pseudomonas and Sulfuritalea were major degrading bacteria in the microbial community. The expression of five microbial genes (PAH-RHDα, PAH-RHDα-GN, PAH-RHDα-GP, nidA, and nidB) in GO amended soils were higher than those devoid of GO. Correlation analysis showed that RHDα, nidA, and nidB were essential contributors to the removal of PAHs. Our findings suggest that appropriate application of GO could be a viable method for enhanced biodegradation of PAHs from contaminated soils.