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Isotherm and kinetic models and cell surface analysis for determination of the mechanism of metal sorption by Aspergillus versicolor
- Gazem, Mufedah A. H., Nazareth, Sarita
- World journal of microbiology & biotechnology 2012 v.28 no.7 pp. 2521-2530
- Aspergillus versicolor, adsorption, biosorption, estuaries, fatty acids, fungi, ion exchange, metal tolerance, metals, models, mycelium, pH, reaction kinetics, scanning electron microscopy
- The isolate Aspergillus versicolor was obtained from an estuary, which is exposed to metal contamination. It was found to have a good metal tolerance and sorption capacity. Further studies revealed that the rate of metal removal from solution is very rapid in the first 5–10 min, and is favoured by a pH of 6.0. The biosorption data obtained was explained by the Freundlich adsorption isotherm model and followed a pseudo-second order kinetics reaction. The fungus showed a higher accumulation of fatty acids when grown in presence of metals as compared to the mycelium grown in absence of the metal; there was also an increase in the saturation index of fatty acids in presence of Cu2+ which serves as a protective mechanism for the fungus. Fourier Transform Infrared, scanning electron microscopy and EDAX analysis indicated that metal removal from solution by A. versicolor occurred by a passive adsorption to the fungal cell surface, involving an ion exchange mechanism.