Remediation of heavy metal contaminated soils by biochar: Mechanisms, potential risks and applications in China.

Polycyclic aromatic hydrocarbons (PAHs) removal by sorption: A review

Polycyclic aromatic hydrocarbons (PAHs) are a large group of chemicals. They represent an important concern due to their widespread distribution in the environment, their resistance to biodegradation, their potential to bioaccumulate and their harmful effects. Several pilot treatments have been implemented to prevent economic consequences and deterioration of soil and water quality. As a promising option, fungal enzymes are regarded as a powerful choice for degradation of PAHs. Phanerochaete chrysosporium, Pleurotus ostreatus and Bjerkandera adusta are most commonly used for the degradation of such compounds due to their production of ligninolytic enzymes such as lignin peroxidase, manganese peroxidase and laccase. The rate of biodegradation depends on many culture conditions, such as temperature, oxygen, accessibility of nutrients and agitated or shallow culture. Moreover, the addition of biosurfactants can strongly modify the enzyme activity. The removal of PAHs is dependent on the ionization potential. The study of the kinetics is not completely comprehended, and it becomes more challenging when fungi are applied for bioremediation. Degradation studies in soil are much more complicated than liquid cultures because of the heterogeneity of soil, thus, many factors should be considered when studying soil bioremediation, such as desorption and bioavailability of PAHs. Different degradation pathways can be suggested. The peroxidases are heme-containing enzymes having common catalytic cycles. One molecule of hydrogen peroxide oxidizes the resting enzyme withdrawing two electrons. Subsequently, the peroxidase is reduced back in two steps of one electron oxidation. Laccases are copper-containing oxidases. They reduce molecular oxygen to water and oxidize phenolic compounds.

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Biodegradation of polycyclic aromatic hydrocarbons (PAHs) by fungal enzymes: A review.

Endophytic bacteria: prospects and applications for the phytoremediation of organic pollutants.

Resource recovery and circular economy from organic solid waste using aerobic and anaerobic digestion technologies.

A PAH-degrading bacterial community enriched with contaminated agricultural soil and its utility for microbial bioremediation.

Contamination and health risk assessment of PAHs in soils and crops in industrial areas of the Yangtze River Delta region, China

Isolation and characterization of 3,5,6-trichloro-2-pyridinol-degrading Ralstonia sp. strain T6.

This investigation provides a novel method of endophyte-aided removal of polycyclic aromatic hydrocarbons (PAHs) from plant bodies. A phenanthrene-degrading endophytic bacterium Pseudomonas sp. Ph6 was isolated from clover (Trifolium pratense L.) grown in a PAH-contaminated site. After being marked with the GFP gene, the colonization and distribution of strain Ph6-gfp was directly visualized in plant roots, stems, and leaves for the first time. After ryegrass (Lolium multiflorum Lam.) roots inoculation, strain Ph6-gfp actively and internally colonized plant roots and transferred vertically to the shoots. Ph6-gfp had a natural capacity to cope with phenanthrene in vitro and in planta. Ph6-gfp degraded 81.1% of phenanthrene (50 mg·L−1) in a culture solution within 15 days. The inoculation of plants with Ph6-gfp reduced the risks associated with plant phenanthrene contamination based on observations of decreased concentration, accumulation, and translocation factors of phenanthrene in ryegrass. Our results will have important ramifications in the assessment of the environmental risks of PAHs and in finding ways to circumvent plant PAH contamination.

Juan Liu

Papers

A PAH-degrading bacterial community enriched with contaminated agricultural soil and its utility for microbial bioremediation.

Contamination and health risk assessment of PAHs in soils and crops in industrial areas of the Yangtze River Delta region, China

Isolation and characterization of 3,5,6-trichloro-2-pyridinol-degrading Ralstonia sp. strain T6.

Isolation, plant colonization potential, and phenanthrene degradation performance of the endophytic bacterium Pseudomonas sp. Ph6-gfp.

Application of biochar to soils may result in plant contamination and human cancer risk due to exposure of polycyclic aromatic hydrocarbons.