Bioleaching of heavy metals from a contaminated soil using indigenous Penicillium chrysogenum strain F1
ABSTRACT Bioleaching of heavy metals from contaminated soil using Penicillium chrysogenum strain F1 was investigated. Batch experiments were performed to compare leaching efficiencies of heavy metals between one-step and two-step processes and to determine the transformation of heavy metal fractions before and after bioleaching. The results showed that two-step process had higher leaching efficiencies of heavy metals than one-step process. When the mass ratio of soil to culture medium containing P. chrysogenum strain F1 was 5% (w/v), 50%, 35%, 9% and 40% of Cd, Cu, Pb and Zn were removed in one-step process, respectively. The two-step process had higher removals of 63% Cd, 56% Cu, 14% Pb and 54% Zn as compared with one-step process. The results of the sequential extraction showed that the metals remaining in the soil were mainly bonded in stable fractions after bioleaching. The results of TEM and SEM showed that during bioleaching process, although the mycelium of P. chrysogenum was broken into fragments, no damage was obviously observed on the surface of the living cell except for thinner cell wall, smaller vacuoles and concentrated cytoplasm. The result implied that P. chrysogenum strain F1 can be used to remove heavy metals from polluted soil.
- SourceAvailable from: Ramalingam Radhakrishnan
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- "The plant growthpromoting bacteria living in soil may be able to reduce susceptibility to heavy metal toxicity (Gupta et al. 2004). Bacteria in the genera Acidithiobacillus, Acetobacter, Acidophilus, Arthrobacter , Pseudomonas and Bacillus are considered to be bioleaching bacteria capable of solubilising heavy metals (Mulligan & Cloutier 2003; Deng et al. 2012). The identification of metaltolerant bacteria is an emerging field of study aimed at overcoming the detrimental effects of heavy metal toxicity on plants. "
ABSTRACT: This study aimed to elucidate the role played by Enterobacter asburiae KE17 in the growth and metabolism of soybeans during copper (100 μM Cu) and zinc (100 μM Zn) toxicity. When compared to controls, plants grown under Cu and Zn stress exhibited significantly lower growth rates, but inoculation with E. asburiae KE17 increased the growth rates of stressed plants. The concentrations of plant hormones (abscisic acid and salicylic acid) and rates of lipid peroxidation were higher in plants under heavy metal stress, while total chlorophyll, carotenoid content, and total polyphenol concentration were lower. While the bacterial treatment reduced the abscisic acid and salicylic acid content and lipid peroxidation rate of Cu-stressed plants, it also increased the concentration of photosynthetic pigments and total polyphenol. Moreover, the heavy metals induced the increased accumulation of free amino acids such as aspartic acid, threonine, serine, glycine, alanine, leucine, isoleucine, tyrosine, proline, and gamma-aminobutyric acid, while E. asburiae KE17 significantly reduced the concentration of free amino acids in metal-affected plants. Co-treatment with E. asburiae KE17 regulated nutrient uptake by enhancing nitrogen content and inhibiting Cu and Zn accumulation in soybean plants. The results of this study suggest that E. asburiae KE17 mitigates the effects of Cu and Zn stress by reprogramming plant metabolic processes. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.Plant Biology 05/2015; DOI:10.1111/plb.12341 · 2.41 Impact Factor
- "However, no physical alteration of the cell surface was observed. These observations suggest the fungus primarily responded to HMs by adsorbing them on external surfaces and preventing cell entry (Deng et al., 2012). "
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- "inoculated soil likely was mainly due to a decrease in soil pH (Deng et al., 2012). Maximum pH reduction from that of the control (pH 6.3) was observed in soil inoculated with both fungi (pH 4.7), followed by soil inoculated with PDR-4 (5.2) and PDR-16 (5.7). "
ABSTRACT: Fungi can facilitate phytoremediation of mine tailing soil containing heavy metal(loid)s (HMs). Penicil-lium aculeatum PDR-4 and Trichoderma sp. PDR-16, isolated from the rhizosphere of Pinus koraiensis inmine tailing soil, exhibited high HM tolerance and plant growth-promoting characteristics. The isolatesincreased available P in a 1:1 (w/w) mixture of soil and liquid media by 14–43% and the bioavailabilityof As, Cu, Pb and Zn was also increased. Both isolates exhibited phosphatase, phytase and siderophoreactivity. ACC deaminase activity was greater in PDR-16 than in PDR-4; IAA was produced by PDR-4 but notby PDR-16. Sorghum-sudangrass (Sorghum bicolor × sudanense) produced 37–95% more aboveground drybiomass and contained 74–128% more chlorophyll in inoculated soil. In soil inoculated with both isolates,HM concentrations increased in roots by 109% (As), 39% (Cu), 50% (Pb) and 38% (Zn), and in shoots by72% (As), 69% (Pb) and 82% (Zn) compared to those of control plants (Cu concentration did not increase inshoots). HM bioavailability and available soil P, as well as plant biomass, chlorophyll content and plant As,Pb and Zn concentrations were highest in soil inoculated with both fungi. Results suggest that inoculatingsoil with P. aculeatum PDR-4 and Trichoderma sp. PDR-16 will be beneficial for phytoremediation andproduction of sorghum-sudangrass as a bioenergy crop in HM-contaminated soils.Ecological Engineering 05/2014; 69:186-191. · 3.04 Impact Factor