Stress responses of fungal species to vanadium

Soil is a non-­renewable resource for human beings and ecosystems.Fungi have important roles in soil and can survive in high concentrations of toxic elements. The potentially toxic elements(PTEs) pose a significant threat on the human health.We investigated relationships between two fungal species,Penicillum citrinum and Paecilomyces lilacinus, isolated from soil with high levels of PTEs and vanadium. These speciesrevealed a tolerance to concentrations up to 6 mM, in relationto growth responses, bioaccumulation and mineraltransformation. Results were based on growth measurements,(GM), tolerance index (TI), scanning electron microscopy (SEM),energy dispersion X-­ray microanalysis (EDXA) and biomassmetal concentrations determined by means of inductivelycoupled plasma mass spectrometry (ICP-MS). Two basidiomycetespecies, Trametes hirsuta and Fomes fomentarius, isolatedfrom unpolluted areas, were also tested. They were able togrown up to 12 mM vanadium and accumulate it to high concentrations: more than 4000 μg/g dry weight for F.fomentarius and 8000 μg/g for T. hirsuta. It was also observedthat vanadium had a stimulatory effect on the growth of F.fomentarius. One-way analysis of variance (ANOVA) and Pearson’scorrelation test were used to test the linearity hypothesis for allthe interactions. Tolerance mechanisms may explain the occurrenceof fungi in metal-polluted habitats and provide opportunities forbioremediation

Kinetic and Equilibrium Studies on the Adsorption of Pb(II), Cd(II) and Cu(II) by Rape Straw

Various kinds of biological materials have been investigated as an alternative biosorbent to treat low-metal-bearing wastewaters. In this study, rape straw (RS), a kind of agricultural waste abundantly available at no cost, was used as an efficient biosorbent for the removal of Pb(II), Cd(II) and Cu(II) ions from aqueous solutions. The maximum adsorption capacity of RS was found to be 61.9 mg g −1 for Pb(II) at pH 4.0, 17.7 mg g −1 for Cd(II) at pH 6.0 and 7.82 mg g −1 for Cu(II) at pH 5.0. The Langmuir isotherm model provides the closest fit to the adsorption data of Pb(II) and Cd(II), whereas the Freundlich model best explained the adsorption of Cu(II). Moreover, the adsorption data of these three metals were all well fitted by the pseudo-second-order kinetic model. Scanning electron microscopic analysis demonstrated a conspicuous surface morphology change in the Pb(II)-, Cd(II)- or Cu(II)-adsorbed adsorbent system. Results of Fourier transform infrared spectrum analysis suggested the involvement of amine, carboxyl, phosphate and hydroxyl groups during adsorption. Based on the study results, it can be concluded that RS can be evaluated as an alternative biosorbent to remove Pb(II), Cd(II) and Cu(II) ions from industrial wastewaters