Heavy metal tolerance traits of filamentous fungi isolated from gold and gemstone mining sites

Abstract

Increased environmental pollution has necessitated the need for eco-friendly clean-up strategies. Filamentous fungal species from gold and gemstone mine site soils were isolated, identified and assessed for their tolerance to varied heavy metal concentrations of cadmium (Cd), copper (Cu), lead (Pb), arsenic (As) and iron (Fe). The identities of the fungal strains were determined based on the internal transcribed spacer 1 and 2 (ITS 1 and ITS 2) regions. Mycelia growth of the fungal strains were subjected to a range of (0–100 Cd), (0–1000 Cu), (0–400 Pb), (0–500 As) and (0–800 Fe) concentrations (mgkg−1) incorporated into malt extract agar (MEA) in triplicates. Fungal radial growths were recorded every three days over a 13-days’ incubation period. Fungal strains were identified as Fomitopsis meliae, Trichoderma ghanense and Rhizopus microsporus. All test fungal exhibited tolerance to Cu, Pb, and Fe at all test concentrations (400–1000 mgkg−1), not differing significantly (p > 0.05) from the controls and with tolerance index >1. T. ghanense and R. microsporus demonstrated exceptional capacity for Cd and As concentrations, while showing no significant (p > 0.05) difference compared to the controls and with a tolerance index >1 at 25 mgkg−1 Cd and 125 mgkg−1 As. Remarkably, these fungal strains showed tolerance to metal concentrations exceeding globally permissible limits for contaminated soils. It is envisaged that this metal tolerance trait exhibited by these fungal strains may indicate their potentials as effective agents for bioremediative clean-up of heavy metal polluted environments.

The Lead [Pb(II)] tolerance and uptake ability of four fungal species, two from the genus Penicillium and two from the genus Talaromyces were investigated in this study. The species were isolated from a polluted tributary and identified to be closest to P. canescens, P. simplicissimum, T. macrosporus and another Talaromyces sp. via PCR targeting their internal transcribed spacer 1 and 4 sequences. All isolates have tolerances for up to 2000 µg/mL and 3000 µg/mL Pb(II) on solid and liquid medium, respective

“…This suggests that the Pb(II) tolerance of the isolates may be independent of the HM concentration differences at this range. This is comparable to the static TI change of 13-day old R. microsporus grown on 100-400 µg/mL Pb(II) (Oladipo et al, 2018).…”

“…Mycoremediation has increasingly gained attention due to its cost-effectivity, remarkable success outcomes, and fungal structural advantages over other rehabilitative agents (Dixit et al, 2015;Kapahi and Sachdeva, 2017). Filamentous fungi can be used in various environments because of their innate competence and responsiveness to fluctuations in temperature, pH, nutrient availability, and HM concentrations (Oladipo et al, 2018). Fungal species can also accumulate higher amounts of HMs compared to plants (Gube, 2016;Kalac and Svoboda, 2000) and bacteria (Ayangbenro and Babalola, 2017;Rhodes, 2014) This ability is based on several fungal constitutive and adaptive physiological and genetic mechanisms that have been summarized extensively in literature (Bellion, 2006;Gadd, 2007;Gube, 2016).…”

Microorganismos tolerantes a metales pesados del pasivo minero Santa Rosa, Jangas (Perú)

“…1A-D), donde el género Fusarium estuvo representada por 6 especies: F. fujikuroi, F. inflexum, F. nygamai, F. oxysporum, F. ramigenum y F. temperatum; el género Penici-llium estuvo representada por 3 especies: P. digitatum, P. rubens y P. vanluykii; mientras que los géneros Aspergillus, Mucor y Rhodotorula sólo tuvieron una especie: A. versicolor, M. griseocynus y R. dairenensis, respectivamente. Estas especies están ampliamente distribuidos en los suelos; pero a su vez varias investigaciones señalan la potencialidad de especies del género Fusarium para la biorremediación de metales pesados (Chen et al 2010, Parameswari et al 2010, Muñoz et al 2012, Iram et al 2013, Oladipo et al 2018a. Del mismo modo varias especies del género Penicillium, Aspergillus, Mucor y Rhodotorula aislados de ambientes contaminados han mostrado capacidades para la bioremediación de metales pesados (Iram et al 2013, Mani & Kumar 2014, Muñoz et al 2012, Oladipo et al 2018a, Parameswari et al 2010, Vargas-García et al 2012.…”

“…Tolerancia a metales pesados.-Se evaluó la capacidad de tolerancia a siete metales pesados con diversos niveles de toxicidad y los resultados se muestran en las Tablas 2 y 3. Oladipo et al (2018a) consideran tolerancia muy baja cuando el índice de tolerancia (IT) se encuentra entre 0.00-0.39, tolerancia baja cuando el IT es 0.40-0.59, tolerancia moderada con IT 0.60-0.79, tolerancia alta con IT 0.80-0.99 y tolerancia muy alta con IT ≥ 1.00; en este sentido se encontró que varios microorganismos mostraron alta y muy alta tolerancia.…”

Lead soaps formation and biodiversity in a XVIII Century wax seal coloured with minium

“…Filamentous fungi proved to be able to accumulate significant amount of metals from their environment. The potential of fungal biomass as agents for biosorption of toxic metals from contaminated sediments has been, in fact, widely evaluated (Sanyal et al, 2005;Taboski et al, 2005;Sun and Shao, 2007;Ezzouhri et al, 2010;Iskandar et al, 2011;Mahish et al, 2015;Oladipo et al, 2018) and several fungal species were screened for their tolerance and uptake capability of lead (Pb). The Ascomycetous genera Aspergillus, Trichoderma, Penicillium, Chaetomium and Phialophora were indicated by different authors as able to survive at high concentrations of Pb, although only Aspergillus niger survived at 5000 mg/L Pb concentration (Iskandar et al, 2011;Ceci et al, 2015).…”