Mechanisms of gold bioaccumulation by filamentous cyanobacteria from gold(III)-chloride complex.
The mechanisms of gold bioaccumulation by cyanobacteria (Plectonema boryanum UTEX 485) from gold(III)-chloride solutions have been studied at three gold concentrations (0.8,1.7, and 7.6 mM) at 25 degrees C, using both fixed-time laboratory and real-time synchrotron radiation absorption spectroscopy (XAS) experiments. Interaction of cyanobacteria with aqueous gold(III)-chloride initially promoted the precipitation of nanoparticles of amorphous gold(I)-sulfide at the cell walls, and finally deposited metallic gold in the form of octahedral (111) platelets (approximately 10 nm to 6 microm) near cell surfaces and in solutions. The XAS results confirm that the reduction mechanism of gold(III)-chloride to metallic gold by cyanobacteria involves the formation of an intermediate Au(I) species, gold(I)-sulfide.
Lengke
Maggy F
MF
Department of Earth Sciences, University of Western Ontario, London, Ontario N6A 5B7, Canada. mlengke@uwo.ca
Ravel
Bruce
B
Fleet
Michael E
ME
Wanger
Gregory
G
Gordon
Robert A
RA
Southam
Gordon
G
D000458:Cyanobacteria / Q000378:metabolism* / Q000648:ultrastructure; D006046:Gold / Q000737:chemistry / Q000378:metabolism*; D017612:Gold Compounds / Q000737:chemistry / Q000378:metabolism*; D046529:Microscopy, Electron, Transmission / Q000379:methods; D049329:Nanostructures / Q000648:ultrastructure; D013997:Time Factors
D017612:Gold Compounds; C038016:gold chloride; D006046:Gold