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.
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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
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ABSTRACT: Bioleaching by Aspergillus niger strain SY1 combined with Fenton-like reaction was optimized to improve trace metal removal and dewaterability of dredged sediments. The major optimized parameters were the duration of bioleaching and H2O2 dose in Fenton-like process (5 days and 2 g H2O2/L, respectively). Bioleaching resulted in the removal of ≈90% of Cd, ≈60% of Zn and Cu, ≈20% of Pb, and in decrease of sediment pH from 6.6 to 2.5 due to organic acids produced by A. niger. After addition of H2O2, Fenton-like reaction was initiated and further metal removal occurred. Overall efficiency of the combined process comprised: (i) reduction of Cd content in sediment by 99.5%, Cu and Zn by >70% and Pb by 39% as a result of metal release bound in all mobilizable fractions; (ii) decrease of sediment capillary suction time (CST) from 98.2 s to 10.1 s (by 89.8%) and specific resistance to filtration (SRF) from 37.4 × 1012 m/kg to 6.2 × 1012 m/kg (by 83.8%), due to reducing amount of extracellular polymeric substances (EPS) by 68.7% and bound water content by 79.1%. The combined process was found to be an efficient method to remove trace metals and improve dewaterability of contaminated dredged sediments.Journal of Hazardous Materials 05/2015; 288. · 4.33 Impact Factor