Tolerance to heavy metals in filamentous fungi isolated from contaminated mining soils in the Zanjan Province, Iran (original) (raw)
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The disposed wastes of zinc industries contain large amounts of heavy metals such as Pb 2+ and Cd 2+. These elements are considered as hazardous elements to human beings and other organisms. This study aims at introducing the fungal isolates that evolved to be compatible with waste deposits during the time and can absorb Pb 2+ and Cd 2+ ions. During the spring and autumn in 2011, eight samples of sediment contaminated by waste were collected from Zanjan zinc industrial zone and fungal isolates were isolated. The degree of tolerance against 0–2500 mg/L Pb 2+ and Cd 2 was measured using minimum inhibitory concentration (MIC) experiment. Results revealed that two Aspergillus sp. isolates namely A.BZ1 isolated in spring and A.PZ1 isolated in the autumn showed the highest resistance and the maximum growth rate. The result of sorption capacity by live and dead biomasses of two isolates against Pb 2+ and Cd 2+ ions with different metal concentrations showed the highest uptake by living biomass of A.PZ1 with 53.75 mg/g and 7.02 mg/g and minimum adsorption in dead biomass was 3.65 and 0.19 mg/g. The results of contact time on isolates sorption revealed that A.PZ1 with 1.715 mg/g sorption has 72.97 % removal efficiency in the first 30 minutes. After the identification of these two isolates and the combination of morphological criteria and sequencing of the ITS˗rDNA region, the A. fumigatus was identified. The prevalence of isolate population, metal tolerance and the genome information in fungi are three traits that can be used as biomarkers for monitoring contaminants in the environment.
HEAVY METAL TOLERANCE OF FILAMENTOUS FUNGI ISOLATED FROM METAL-CONTAMINATED SOIL
– A total of seven soil fungi, identified as Alternaria solani, Aspergillus (two species), Fusarium sp., Helminthosporium oryzae, Rhizopus sp., and Trichoderma sp. were isolated from the heavy metal contaminated soil sludge around the thermal power plant premises of Hooghly district of West Bengal, India. The isolates showed maximum resistance to zinc with minimum inhibitory concentrations (MIC) ranging from 5-25 mM and moderate resistance to cadmium and nickel with MIC ranging from 2-5 mM each. Metal tolerance index determined by observing growth of the fungi at 1 mM concentrations of each metal was also varied for the three metals. Trichoderma F14 which had highest tolerance to all the three metals was able to remove substantial amount of all the three metals from liquid media. When the isolate was grown separately in presence of Cd (100-500 mgL-1), Ni (50-250 mgL-1), and Zn (500-1500 mgL-1) it accumulated Cd (5.78-30.59 mgg-1), Ni (4.26-31.40 mgg-1), and Zn (16.33-25.42 mgg-1), respectively. Thus the fungal isolate has potential metal remediation property.
Environmental Technology & Innovation, 2021
Due to various anthropogenic activities, different heavy metals like arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), mercury (Hg) and nickel (Ni) accumulate in the soils of industrial areas. In the current study, contaminated soil was collected from Yuepu industrial area of Shanghai, China. Soil analysis revealed the presence of Pb and Cu in high concentrations, ranging from 125.9-128.0 mg/kg and 98.4-100.2 mg/kg, respectively. These soil samples were further used to isolate metal tolerant microbes. Subsequent screening resulted in the isolation of four major fungal species including Fusarium fujikuroi, Fusarium solani, Trichoderma citronoviridae and Trichoderma reesei. Molecular characterization of isolated fungi was performed and amplified sequences were deposited in GenBank NCBI database. Metal tolerance and biosorption capacity of these fungal strains towards lead and copper were tested. Fungal strains were exposed to increasing concentrations (100-1000 ppm) of chlorides of lead and copper and the tolerance of the selected fungi was evaluated by measuring the minimum inhibitory concentrations (MIC). The range of MIC values was found to be 400 ppm to 1000 ppm. The tolerance index of all the tested fungi was calculated and T. citronoviridae was observed to be tolerant at 1 mM concentration of lead while F. solani was the most tolerant species at 1 mM concentration of copper. The highest biosorption capacity of Pb was exhibited by T. citronoviridae, while T. reesei showed the best absorption capacity of Cu followed by F. solani. Scanning electron microscopy (SEM) showed visible adsorption of metal on fungal mycelia and suggested it to be the mechanism of metal removal. On the basis of these findings, it could be concluded that T. citronoviridae and F. solani are the potential mycoremediation microbes in Pb and Cu contaminated soils, respectively.
Bioresource Technology, 2007
Heavy metal analysis of agricultural field soil receiving long-term (>20 years) application of municipal and industrial wastewater showed two-to five-fold accumulation of certain heavy metals as compared to untreated soil. Metal-resistant fungi isolated from wastewater-treated soil belonged to genera Aspergillus, Penicillium, Alternaria, Geotrichum, Fusarium, Rhizopus, Monilia and Trichoderma. Minimum inhibitory concentrations (MIC) for Cd, Ni, Cr, Cu, and Co were determined. The MIC ranged from 0.2 to 5 mg ml À1 for Cd, followed by Ni (0.1-4 mg ml À1 ), Cr (0.3-7 mg ml À1 ), Cu (0.6-9 mg ml À1 ) and for Co (0.1-5 mg ml À1 ) depending on the isolate.
Biologija, 2012
In the present study the tolerance level of different fungi (Aspergil lus flavus, Aspergillus niger, Aspergillus versicolor, Scopulariop sis sp., Curvularia sp., Helminthosporium sp., Humicola grisea sp., Nannizzia sp., and Fusarium sp.) were investigated towards heavy metals which were isolated from contaminated peri-urban agricultural soils of Faisalabad. The concentration of heavy metals in soil is determined by using atomic absorption spectrophotometer. The degree of tolerance of fungi was measured by minimum inhibitory concentration in the presence of different concentrations of heavy metals (Cr and Pb) and compared to control sample. Tolerance analysis depicts that growth rate of fungal isolates decreased with increase in concentrations and few isolates are tolerant, some are moderately tolerant and some are sensitive towards metal concentrations of Cr and Pb. Most of the isolates were tolerant to metals. Among all tested fungal strains, few isolates of Aspergillus flavus and Aspergillus niger, Fusarium were tolerant to Cr and Pb. Thus these tolerant isolates can be used for the purpose of bioremediation in future.
The remediation of heavy metals polluted soil using biosystems involves the use of plants and fungi species for the extraction of metals from soil. To streamline the process of bioremediation of soil polluted with heavy metals using higher fungi, those species should be chosen with a high capacity to absorb metals and environmental factors can be controlled so that the accumulation of these elements to be favored. Heavy metal absorption by higher fungi is influenced primarily by the species, but also by soil pH and concentration of other metals in the soil. The interaction of chemical elements can be synergistic and / or antagonistic, and the reactions that lead to the creation of a chemical imbalance are a chemical stress for the fungi. The main correlations were observed between the Cu content in soil and concentration of Cu and Zn in fungi, elements which have a moderate positive correlation, but also between Sn content in the soil and the content of Co and Ni in the fungus. Mode...
Heavy metal tolerance traits of filamentous fungi isolated from gold and gemstone mining sites
Brazilian Journal of Microbiology, 2017
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.
Journal of Pure and Applied Microbiology
In this study fungal profiles of agricultural field soil irrigated with industrial wastewater and sewage containing varying concentrations of heavy metals (Chromium, Nickel, Cobalt, Copper and Cadmium) have been investigated. The impact of long term heavy metal contamination on emergence of heavy metal tolerant soil fungal population, changes in morphological diversity and metal tolerance limits among isolated fungi was studied. The agricultural field soil received long term (>20 years) wastewater application showed metal accumulation compared to the untreated soil. The viable count of soil fungal population from three different agricultural field soil was found in order of 10 5 to 10 4 CFU gm-1 of soil indicating a normal viable count with little variations. Viable plate count of fungal population on metal amended plates decreased with increasing concentration of tested metals (Cr 6+ , Cd ++. Cu ++ , Co ++ and Ni ++) from 100 to 400 µgml-1. The decrease was higher on cadmium amended plates and lower against Chromium. The control site, which did not receive wastewater application showed relatively less metal tolerant fungal viable count on Cd ++ and Ni ++ plates when compared at 100 µgml-1 as compared to contaminated sites. Similarly, presence of metal tolerant fungal population was also observed from wastewater sample. The common soil fungi isolated and characterized from metal amended plates belong to 18 genera and 15 unidentified species. Occurrence of different fungal genera from site A B and C indicated different patterns of decrease on different metal amended plates with increasing concentration. Among these 73 isolated fungal species a high level of tolerance was recorded to Cr 6+ followed by Cu ++ , Co ++ and Ni ++ while the lowest level of tolerance was for Cd ++. The minimum inhibitory concentration (MIC) values of 73 metal tolerant fungal isolates, was ranged from 200 to 2000 μgml-1 against one or more heavy metals. The level of tolerance to heavy metals also varied even among the isolates of single genus. Aspergillus was the predominant genus recovered from contaminated soils where the MIC values are highly varied among different isolates of Aspergillus. The current study found that long term release of wastewater has not disturbed the fungal population dynamics in contaminated sites as compared to uncontaminated sites. However, it tends to exert selective pressure on fungal populations of soil, leading to the development of increased level of metal tolerance in fungal species.
Tolerance potential of fungi isolated from polluted soil of Multan, Pakistan
Filamentous fungi were isolated from polluted peri-urban area of Multan, Pakistan and the tolerance potential of fungal strains i.e., Aspergillus niger against specific metals Cr(NO3)3, Pb(NO3)2 and ZnCl2 were tested on Potato Dextrose Agar (PDA) plate. The degree of tolerance is measured through minimum inhibitory concentration (by applying different concentrations of metals). Tolerance potential showed either tested isolates are tolerant, moderately tolerant or sensitive. The findings of present study is depicted that Aspergillus niger showed different tolerance behaviour for different metals at different concentrations such as chromium and lead are more tolerated as compared to Zinc. The knowledge of the present study will be helpful for further research of biosorption and bioremediation potential of fungi and used them for applied side.
2020
Simple Summary In this study, cadmium, chromium, and lead tolerant microbes have been isolated from contaminated mining soil and characterized. Molecular characterization of isolated fungi was performed and amplified sequences were deposited in the GenBank NCBI database. Metal tolerance of the various strains has been determined by measuring the minimum inhibitory concentrations (MICs) and the tolerance indexes of all the tested strains against Cd, Cr, and Pb. Bioaccumulation capacities of Trichoderma harzianum and Komagataella phaffi have also been assessed. These findings helped us find a novel strain of Komagataella phaffi and suggested it to be the potential mycoremediation microbe to alleviate the contamination of Cd, Cr, and Pb. Future studies of this fungal strain can help us to understand its resistance mechanism against other heavy metals, too. Abstract Rapidly increasing industry has resulted in greater discharge of hazardous chemicals in the soil. In the current study, so...