title: Mechanisms of gold bioaccumulation by filamentous cyanobacteria from gold(III)-chloride complex.
abstract: 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.
authors.affiliation: Department of Earth Sciences, University of Western Ontario, London, Ontario N6A 5B7, Canada. mlengke@uwo.ca
authors.forename: Maggy F
authors.initials: MF
authors.lastname: Lengke
authors.forename: Bruce
authors.initials: B
authors.lastname: Ravel
authors.forename: Michael E
authors.initials: ME
authors.lastname: Fleet
authors.forename: Gregory
authors.initials: G
authors.lastname: Wanger
authors.forename: Robert A
authors.initials: RA
authors.lastname: Gordon
authors.forename: Gordon
authors.initials: G
authors.lastname: Southam
mesh_terms: 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
chemical_list: D017612:Gold Compounds; C038016:gold chloride; D006046:Gold