Concomitant Microbial Generation of Palladium Nanoparticles and Hydrogen To Immobilize Chromate

Abstract

The catalytic properties of various metal nanoparticles have led to their use in environmental remediation. Our aim is to develop and apply an efficient bioremediation method based on in situ biosynthesis of bio-Pd nanoparticles and hydrogen. C. pasteurianum BC1 was used to reduce Pd(II) ions to form Pd nanoparticles (bio-Pd) that primarily precipitated on the cell wall and in the cytoplasm. C. pasteurianum BC1 cells, loaded with bio-Pd nanoparticle in the presence of glucose, were subsequently used to fermentatively produce hydrogen and to effectively catalyze the removal of soluble Cr(VI) via reductive transformation to insoluble Cr(III) species. Batch and aquifer microcosm experiments using C. pasteurianum BC1 cells loaded with bio-Pd showed efficient reductive Cr(VI) removal, while in control experiments with killed or viable but Pd-free bacterial cultures no reductive Cr(VI) removal was observed. Our results suggest a novel process where the in situ microbial production of hydrogen is directly coupled to the catalytic bio-Pd mediated reduction of chromate. This process offers significant advantages over the current groundwater treatment technologies that rely on introducing preformed catalytic nanoparticles into groundwater treatment zones and the costly addition of molecular hydrogen to above ground pump and treat systems.

Bio-Reclamation of Strategic and Energy Critical Metals from Secondary Resources

“…It has been observed that the microbial activity is helpful to generate an in situ reducing environment for metal ion reduction and the subsequent catalytic reactions as well [60][61][62]. Lenz et al [63] showed the important role of metal species in reduction potential and bacterial uptake efficiency.…”

Effect of fluid shear stress on catalytic activity of biopalladium nanoparticles produced by Klebsiella Pneumoniae ECU-15 on Cr(VI) reduction reaction

“…All these results proved that the generation of the bioPd(0) was through the reduction of the Pd(II) to Pd(0) on the surface of the K. pneumoniae ECU-15 cells. The location of the bioPd(0) nanoparticles generated might be caused by the distribution and properties of hydrogenase and other enzymes involved in Pd(II) reduction [11]. However, Rotaru found that the cell surface functional groups really played a catalytic function role for the Pd(II) reduction to the bioPd(0) [3].…”

“…Many fermentative species could produce hydrogen during fermentation and subsequently reduce Pd(II) to Pd(0). An addition of Pd(II) to the fermenting culture of Clostridium pasteurianum could result in the formation of Pd(0) nanoparticles on the bacterial cell wall and in the cytoplasm [11]. Klebsiella pneumoniae is a potential biohydrogen producer [12] and has the ability to bioreduce Pd(II) [13].…”

A Novel Aerobic Mechanism for Reductive Palladium Biomineralization and Recovery byEscherichia coli

“…Other organisms capable of this metal bioreduction include the Gram-negative bacteria Shewanella oneidensis (De Windt et al 2005), Escherichia coli (Deplanche et al , 2014Mabbett et al 2006), Pseudomonas putida, Cupriavidus necator (Søbjerg et al 2009), Cupriavidus metallidurans , Paracoccus denitrificans , Rhodobacter sphaeroides (Redwood et al 2008), Rhodobacter capsulatus , and the Gram-positive bacteria Bacillus sphaericus (Creamer et al 2007), Arthrobacter oxyidans (Deplanche et al 2014;Wood et al 2010), Micrococcus luteus (Deplanche et al 2014), Staphylococcus sciuri (Søbjerg et al 2009) and Clostridium pasteurianum (Chidambaram et al 2010).…”