Fungi possess the biochemical and ecological capacity to degrade environmental organic chemicals and to decrease the risk associated with metals, metalloids and radionuclides, either by chemical modification or by influencing chemical bioavailability. Furthermore, the ability of these fungi to form extended mycelial networks, the low specificity of their catabolic enzymes and their independence from using pollutants as a growth substrate make these fungi well suited for bioremediation processes. However, despite dominating the living biomass in soil and being abundant in aqueous systems, fungi have not been exploited for the bioremediation of such environments. In this Review, we describe the metabolic and ecological features that make fungi suited for use in bioremediation and waste treatment processes, and discuss their potential for applications on the basis of these strengths.

Untapped potential: exploiting fungi in bioremediation of hazardous chemicals

Arbuscular mycorrhizal fungal responses to abiotic stresses: A review.

https://digital.csic.es/bitstream/10261/146158/3/Advanced_technologies_remediation_2017_Postprint.pdf

Advanced technologies for the remediation of pesticide-contaminated soils

Excessive use of pesticides and herbicides is a major environmental and health concern worldwide. Atrazine, a synthetic triazine herbicide commonly used to control grassy and broadleaf weeds in crops, is a major pollutant of soil and water ecosystems. Atrazine modifies the growth, enzymatic processes and photosynthesis in plants. Atrazine exerts mutagenicity, genotoxicity, defective cell division, erroneous lipid synthesis and hormonal imbalance in aquatic fauna and nontarget animals. It has threatened the sustainability of agricultural soils due to detrimental effects on resident soil microbial communities. The detection of atrazine in soil and reservoir sites is usually made by IR spectroscopy, ELISA, HPLC, UPLC, LC–MS and GC–MS techniques. HPLC/LC–MS and GC–MS techniques are considered the most effective tools, having detection limits up to ppb levels in different matrices. Biodegradation of atrazine by microbial species is increasingly being recognized as an eco-friendly, economically feasible and sustainable bioremediation strategy. This review presents the toxicity, analytical techniques, abiotic degradation and microbial metabolism of atrazine.

Toxicity, degradation and analysis of the herbicide atrazine

The soil environment is interesting and complicated. There are so many interactions taking place in the soil, which determine the properties of soil as a medium for the growth and activities of plants and soil microorganisms. The soil fungi, arbuscular mycorrhiza (AM), are in mutual and beneficial symbiosis with most of the terrestrial plants. AM fungi are continuously interactive with a wide range of soil microorganisms including nonbacterial soil microorganisms, plant growth promoting rhizobacteria, mycorrhiza helper bacteria and deleterious bacteria. Their interactions can have important implications in agriculture. There are some interesting interactions between the AM fungi and soil bacteria including the binding of soil bacteria to the fungal spore, the injection of molecules by bacteria into the fungal spore, the production of volatiles by bacteria and the degradation of fungal cellular wall. Such mechanisms can affect the expression of genes in AM fungi and hence their performance and ecosystem productivity. Hence, consideration of such interactive behavior is of significance. In this review, some of the most important findings regarding the interactions between AM fungi and soil bacteria with some new insights for future research are presented.

Interactions between arbuscular mycorrhizal fungi and soil bacteria

The effects of an arbuscular mycorrhizal (AM) fungus ( Glomus etunicatum ) on atrazine dissipation, soil phosphatase and dehydrogenase activities and soil microbial community structure were investigated. A compartmented side-arm (‘cross-pot’) system was used for plant cultivation. Maize was cultivated in the main root compartment and atrazine-contaminated soil was added to the side-arms and between them 650 or 37 μm nylon mesh was inserted which allowed mycorrhizal roots or extraradical mycelium to access atrazine in soil in the side-arms. Mycorrhizal roots and extraradical mycelium increased the degradation of atrazine in soil and modified the soil enzyme activities and total soil phospholipid fatty acids (PLFAs). Atrazine declined more and there was greater stimulation of phosphatase and dehydrogenase activities and total PLFAs in soil in the extraradical mycelium compartment than in the mycorrhizal root compartment when the atrazine addition rate to soil was 5.0 mg kg −1 . Mycelium had a more important influence than mycorrhizal roots on atrazine degradation. However, when the atrazine addition rate was 50.0 mg kg −1 , atrazine declined more in the mycorrhizal root compartment than in the extraradical mycelium compartment, perhaps due to inhibition of bacterial activity and higher toxicity to AM mycelium by atrazine at higher concentration. Soil PLFA profiles indicated that the AM fungus exerted a pronounced effect on soil microbial community structure.

/pdf/influence-of-glomus-etunicatum-zea-mays-mycorrhiza-on-1se7skg7nn.pdf

Influence of Glomus etunicatum/Zea mays mycorrhiza on atrazine degradation, soil phosphatase and dehydrogenase activities, and soil microbial community structure

DDT uptake by arbuscular mycorrhizal alfalfa and depletion in soil as influenced by soil application of a non-ionic surfactant.

Enhanced dissipation of phenanthrene in spiked soil by arbuscular mycorrhizal alfalfa combined with a non-ionic surfactant amendment

Phenanthrene uptake by Medicago sativa L under the influence of an arbuscular mycorrhizal fungus

A greenhouse pot experiment was carried out to investigate the effect of the arbuscular mycorrhizal fungus Glomus etunicatum on the uptake of atrazine (ATR) and cadmium (Cd) from soil by maize (Zea mays L.). Mycorrhizal colonization led to an increase in the accumulation of Cd and ATR in maize roots but a decrease in the shoots. Atrazine alleviated the adverse effects of Cd on maize growth, and this was more pronounced in the inoculated plants. An increase in Cd accumulation by maize roots was observed when ATR was also present. After harvest, the residual ATR concentration in the soil decreased markedly. With mycorrhizal inoculation the amount of residual ATR decreased more in the bulk soil but less in the rhizosphere soil compared to the noninoculated controls. Cadmium application significantly decreased the ATR residual concentrations in both the rhizosphere and bulk soils irrespective of inoculation treatment.

/pdf/uptake-of-atrazine-and-cadmium-from-soil-by-maize-zea-mays-l-3dy32zvzam.pdf

Naiying Wu

Papers

Influence of Glomus etunicatum/Zea mays mycorrhiza on atrazine degradation, soil phosphatase and dehydrogenase activities, and soil microbial community structure

DDT uptake by arbuscular mycorrhizal alfalfa and depletion in soil as influenced by soil application of a non-ionic surfactant.

Enhanced dissipation of phenanthrene in spiked soil by arbuscular mycorrhizal alfalfa combined with a non-ionic surfactant amendment

Phenanthrene uptake by Medicago sativa L under the influence of an arbuscular mycorrhizal fungus

Uptake of atrazine and cadmium from soil by maize (Zea mays L.) in association with the arbuscular mycorrhizal fungus Glomus etunicatum.