Abstract
Abstract
Chromium pollution has grave consequences and can cause serious damage to biological systems. Recently, polyamines have received significant attention due to their biotechnological interests. This study is aiming to test the effect of putrescine on hexavalent chromium [Cr(VI)] removal by Wickerhamomyces anomalus and cell surface physicochemical properties of this strain. The experiment was conducted in modified yeast extract, peptone, and glucose medium contaminated with 50 mg/L Cr(VI) and treated with putrescine at 0 (control), 1, and 10 mM. Results showed that putrescine enhanced Cr(VI) removal potential, accompanied by an increased hydrophobicity and electron acceptor character and a decreased electron donor character of surface cells. This putrescine action was dependent on its concentration with a higher effect at 10 mM. At this concentration, scanning electron microscope/energy dispersive X-ray analysis showed a modification of the chemical composition and a high concentration of nitrogen on yeast cell wall. Sorption data were modeled using the pseudofirst-order and pseudosecond-order equations. Results indicated that a pseudosecond-order kinetic model could better describe the metal sorption kinetics by W. anomalus cells at different putrescine concentrations. This work highlights the possibility of enhancement of wastewater treatment, especially heavy metal uptake, by modifying cell surface characteristics.
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