Overview of Approaches to Improve Rhizoremediation of Petroleum Hydrocarbon-Contaminated Soils

Abstract

Soil contamination with petroleum hydrocarbons (PHCs) has become a global concern and has resulted from the intensification of industrial activities. This has created a serious environmental issue; therefore, there is a need to find solutions, including application of efficient remediation technologies or improvement of current techniques. Rhizoremediation is a green technology that has received global attention as a cost-effective and possibly efficient remediation technique for PHC-polluted soil. Rhizoremediation refers to the use of plants and their associated microbiota to clean up contaminated soils, where plant roots stimulate soil microbes to mineralize organic contaminants to H2O and CO2. However, this multipartite interaction is complicated because many biotic and abiotic factors can influence microbial processes in the soil, making the efficiency of rhizoremediation unpredictable. This review reports the current knowledge of rhizoremediation approaches that can accelerate the remediation of PHC-contaminated soil. Recent approaches discussed in this review include (1) selecting plants with desired characteristics suitable for rhizoremediation; (2) exploiting and manipulating the plant microbiome by using inoculants containing plant growth-promoting rhizobacteria (PGPR) or hydrocarbon-degrading microbes, or a combination of both types of organisms; (3) enhancing the understanding of how the host–plant assembles a beneficial microbiome, and how it functions, under pollutant stress. A better understanding of plant–microbiome interactions could lead to successful use of rhizoremediation for PHC-contaminated soil in the future.

Salix purpurea and Eleocharis obtusa Rhizospheres Harbor a Diverse Rhizospheric Bacterial Community Characterized by Hydrocarbons Degradation Potentials and Plant Growth-Promoting Properties

“…Industrial activities such as mining for minerals, oil and gas extraction, inorganic fertilizer-based agriculture, and industrial waste disposal, are all associated with environmental contamination risks which represent a global challenge [1]. Among pollutants, petroleum hydrocarbons (PHCs) are of great concern and can pose a high risk in oil spills, and environmental contamination of aquatic and terrestrial ecosystems.…”

In-Depth Characterization of Plant Growth Promotion Potentials of Selected Alkanes-Degrading Plant Growth-Promoting Bacterial Isolates

“…Human activities related to the petroleum and gas industry, such as exploration, extraction, refining, storage, and shipping, are polluting soil and water environments with petroleum hydrocarbons (PHCs; Alotaibi et al, 2021a ). Aliphatic hydrocarbons (alkanes) are saturated hydrocarbons, representing the main constituents of crude oil, and are major soil contaminants ( Chénier et al, 2003 ; Stroud et al, 2007 ).…”

“…The use of the usual physical and chemical methods to cope with PHC contamination have shown many limitations ( Alotaibi et al, 2021a ). These conventional approaches are very expensive, only work for specific organic compounds and do not often result in the complete degradation of the contaminants; in addition, they are not environmentally friendly as they contribute to greenhouse gas emissions ( Kuiper et al, 2004 ; Pilon-Smits, 2005 ; Behera, 2014 ).…”

“…On the other hand, a biological method such as phytoremediation that relies on the plant–microbe partnership is a promising strategy for the remediation of soils contaminated with aliphatic hydrocarbons. Phytoremediation requires less maintenance effort, minimizes site disturbances, and is a cost-effective and less destructive approach ( Alotaibi et al, 2021a ).…”

Native Heavy Metal-Tolerant Plant Growth Promoting Rhizobacteria Improves Sulla spinosissima (L.) Growth in Post-Mining Contaminated Soils

“…Besides their direct and indirect positive effects on biomass production, plant-associated bacteria can also contribute to an increase in metal availability and uptake, and to a decrease in metal phytotoxicity [ 11 ]. In recent years, PGPR have proven powerful for improving the phytoremediation of petroleum and other contaminants [ 12 , 13 ]. PGPR-assisted phytoremediation technology can provide better plant growth and remediate contaminated soils compared with using plants alone [ 14 , 15 ].…”