Heavy metal capture by autochthonous yeasts from a volcanic influenced environment of Patagonia

Abstract

Heavy metals at elevated concentrations are a major threat to agricultural and human health. Typically, human activities tend to release these metals to the environment in aqueous solutions, generating high levels of pollution due to the mobility of the heavy metals. The aim of the present work was to assess heavy metal tolerance in yeasts isolated from Río Agrio - Lake Caviahue volcanic acidic aquatic environment and to evaluate the capacity of selected strains to capture metals in acidic culture media conditions. The ability of three yeast species, Cryptococcus agrionensis, Cryptococcus sp. 2, and Coniochaeta fodinicola, to tolerate and capture metals in live cultures has been evaluated. These three yeast species showed high tolerance to low pH and elevated concentrations of metals, thus implying their autochthonous status. Minimal inhibitory concentration (MIC) for growth obtained for these isolates showed elevated tolerance to the six heavy metals evaluated and were significantly higher than those registered for other microorganisms. C. agrionensis was able to capture 15.80 mg (g biomass) of Cu (MIC: 0.22 g L ), Cryptococcus sp. 2 was able to capture 36.25 and 65.28 mg (g biomass) of Ni and Zn , respectively (MIC: 0.56 and 1.68, respectively), and C. fodinicola was able to capture 67.11 mg (g biomass) of Zn (MIC: 3.75). This work reported the ability of yeasts to capture metals in acidic conditions for the first time. We hope that it represents the step-stone for future researches in the ability and metabolism of yeasts form acidic aquatic environment related to metal tolerance and capture.

Fungal Community Structure and As-Resistant Fungi in a Decommissioned Gold Mine Site

“…A species belonging to this genus, namely, C. musci , was isolated from another decommissioned mine site and found to exhibit the highest tolerance to As(V) as compared to other yeasts isolated from the same site (Vadkertiová et al, 2016 ). The ability of some Cryptococcus species to tolerate high metal concentrations was already reported (Russo et al, 2016 ) and ascribed to their high polyphosphate accumulation capacity (Andreeva et al, 2014 ). Noteworthy, for another species, such as, Cryptococcus humicola , the As-resistance was found to be due to its ability to convert chromated copper arsenate to volatile forms, such as, trimethylarsine (Bentley and Chasteen, 2002 ).…”

Fungi inhabiting knotwood ofPinus sylvestrisinfected byPorodaedalea pini

“…It is a rare species, with no previous reports of its occurrence on plant substrates. Russo, Libkind, Goraudo, and Delgado () considered C. fodinicola as an autochthonous yeast in a volcanic‐influenced environment of Patagonia. Recently, however, it has also been found at a uranium mine site in Australia where it was able to take up and bind the uranium ions.…”

“…Coniochaeta hoffmannii belonged to acidophile yeasts in acid rock drainage of Iberian Pyrite Belt (Gadanho, Libkind, & Sampaio, ). Coniochaeta fodinicola occurs in the most extremely acidic aquatic environments, with pH as low as 1.7–1.8 (Russo et al., ; Vazquez‐Campos, Kinsela, Waite, Collins, & Neilan, ). Lecanora conizaeoides colonizes substrates with pH < 4 (LaGreca & Stutzman, ).…”

“…hoffmannii ( anamorph: L. hoffmannii ) and R. atrovirens can be serious human pathogens (De Hoog & Guarro, ). Another, C. fodinicola , is considered to have potential for application for bioremediation processes in acidic conditions (Russo et al., ). Pinus sylvestris knots could be used as the source of suitable isolates for the latter fungus.…”

Yeasts from the Maritime Antarctic: tools for industry and bioremediation

“…Control assays without either metals or a yeast inoculation were also performed. When the incubation time had elapsed, the final state of growth was recorded visually (Russo et al 2016).…”