Bioremediation and extracellular synthesis of copper nanoparticles from wastewater using Yarrowia lipolytica AUMC 9256

Abstract

T HIS THE FIRST study describing the rapid extracellular synthesis of copper nanoparticles during the bioremediation of copper by living, autoclaved and dried biomass of Yarrowia lipolytica AUMC 9256. The time course growth in the presence of different concentrations of Cu(II) was studied. The minimum inhibitory concentration value of Y.lipolytica AUMC 9256 for Cu(II) was 1900mg/L. The cellular localization of bioaccumulated copper ions was assessed. Maximum uptake capacities were accomplished at pH 6.0, initial metal ion concentration 450mg/L, biomass dosage 1g/L and contact time 180min for live cells, 90min for autoclaved and 30min for dried biomass. Copper nanoparticles were characterized by UV-Visible spectrophotometer and transmission electron microscopy. They were all spherical in shape with an average size of 32.85nm (live), 22.34nm (autoclaved) and 15.62nm (dried). The occurrence of extracellular complexation, precipitation, adsorption onto cell wall and sequestration of needle-, rod-shaped precipitates within central large vacuole during Cu(II) uptake by live biomass were found out by transmission electron microscopy. Fourier Transform Infrared spectroscopy confirmed that mannans, phosphorus, P=S stretching, C-S stretching, M-O and ring deformation were more included in Cu(II) uptake by dried biomass. Energy dispersive X-ray microanalysis confirmed the presence of high-intensity characteristic peaks of Cu(II) and a sharp reduction of atomic % of phosphorus and potassium on the cell wall. X-ray powder diffraction patterns of Cu(II)-loaded biomass confirmed their crystalline nature. The removal of copper from ceramic industry wastewater was carried out by dried biomass effectively.

A Comparative Study on Heavy Metal Removal from CCA-Treated Wood Waste by Yarrowia lipolytica: Effects of Metal Stress

“…In addition, biofilm formation is another way to resist metal ion stress. Moreover, the extracellular synthesis of Cu-nanoparticles of Y. lipolytica was also a pathway in response to Cu stress [35].…”