Metabolic adaptation of fungal strains in response to contamination by polychlorinated biphenyls

Abstract

Polychlorinated biphenyls (PCBs) represent a large group of recalcitrant environmental pollutants. Up to now, many studies have focused on bioremediation of PCBs by fungal strains; however the mechanisms of adaptation of these strains towards PCBs remain unknown despite their importance in developing effective bioremediation processes. We studied five species, each consisting of two strains isolated either from PCB-polluted or unpolluted substrates (control strains). We investigated their responses to PCB contamination by studying their tolerance to PCBs, their ability to reduce these pollutants and their expression level of Laccase genes. In Thermothelomyces thermophila, Thermothelomyces heterothallica, Thermoascus crustaceus and Fusarium solani, all the studied strains showed a similar tolerance and PCB degradation regardless of their origin. In Schizophyllum commune, while both strains showed similar resistance to PCBs i.e PCBs and their degradation products presented no toxicity for these strains, the rate of PCB degradation of the strain from a PCB-polluted environment was significantly slightly higher. The PCB degradation did not correlate with the expression level of genes encoding Laccases. These results demonstrate that the tolerance and PCB degradation by the fungal strains, which did not involve Laccase activities, required different adaptation systems which seem to be constitutive or rapidly inducible by PCB according to the fungal species.

Biodegradation of Atrazine and Ligninolytic Enzyme Production by Basidiomycete Strains

“…Many strains also differed in pigmentation ( gure 2). Changes in growth rates, pigmentation and spore production are common in fungi growing in toxic environments (Périgon et al, 2019). After cultivating Mucor plumbeus on pentachlorophenol contaminated medium, Carvalho et al (2015) observed an overexpression of proteins associated to increased energy demand, changes on cell wall structure and cytoskeleton, as well as responses to oxidative stress (like cytochrome c oxidase and HSP70 chaperones).…”

Potentiality of Native Ascomycete Strains in Bioremediation of Highly Polychlorinated Biphenyl Contaminated Soils

“…While most studies have explored the ability of ligninolytic Basidiomycete strains in the mycoremediation of PCB-polluted soils [ 2 , 4 , 14 , 15 , 31 ] and have shown in most cases underwhelming results [ 16 ], very few studies have investigated the potentiality of Ascomycete strains isolated from PCB-polluted soils to degrade these recalcitrant pollutants. These endogenous strains seemed to possess high potential capacities to degrade PCBs in liquid medium comparable to those of ligninolytic basidiomycete strains [ 17 , 21 , 22 , 32 ] and could potentially grow easily in their native soil without being hindered by competition with other native strains. In this study, the abilities of the consortium of five Ascomycetes strains, P. chrysogenum, P. canescens , P. citreosulfuratum , A. jensenii , and Ac.…”

“…Ascomycete strains isolated from PCB polluted soils are naturally selected by their habitat and potentially able to feed on these pollutants. Similarly to ligninolytic strains, they are able to degrade PCBs efficiently in a liquid medium probably through constitutive enzymes or PCBs-inducible enzymes [ 21 , 22 ]. Despite these interesting potentials, only one study has appraised the biodegradation of PCBs in soils and sediments by native Ascomycete strains [ 5 ].…”

Biodegradation of atrazine and ligninolytic enzyme production by basidiomycete strains

“…Changes in growth rates, pigmentation and spore production are common in fungi growing in toxic environments [27]. After cultivating Mucor plumbeus on pentachlorophenol contaminated medium, Carvalho et al [28] observed an overexpression of proteins associated to increased energy demand, changes on cell wall structure and cytoskeleton, as well as responses to oxidative stress (like cytochrome c oxidase and HSP70 chaperones).…”