TY - JOUR
T1 - Biogeochemical gold cycling selects metal-resistant bacteria that promote gold particle transformation
AU - Sanyal, Santonu Kumar
AU - Shuster, Jeremiah
AU - Reith, Frank
N1 - Funding Information:
Funding for this research was made possible by the Australian Research Council Future Fellowship (ARC-FT100150200) awarded to F. Reith.
Publisher Copyright:
© 2019 FEMS 2019.
PY - 2019/7/1
Y1 - 2019/7/1
N2 - Bacteria catalyze the dissolution and re-precipitation of gold, thereby driving the biogeochemical cycle of gold. Dissolution of gold/silver and re-precipitation of gold transforms gold particles by increasing gold purity. While soluble gold complexes are highly cytotoxic, little is known about how gold cycling affects bacterial communities residing on gold particles. Micro-analysis of gold particles obtained from Western Australia revealed porous textures and aggregates of pure gold nanoparticles, attributable to gold dissolution and re-precipitation, respectively. By interpreting structure and chemistry of particles, the kinetics of gold biogeochemical cycling at the site was estimated to be 1.60 × 10-9 M year-1. Bacterial communities residing on particles were composed of Proteobacteria (42.5%), Bacteroidetes (20.1%), Acidobacteria (19.1%), Firmicutes (8.2%), Actinobacteria (3.7%) and Verrucomicrobia (3.6%). A bacterial enrichment culture obtained from particles contained a similar composition. Exposure of enrichments to increasing concentrations of soluble gold decreased community diversity and selected for metal-resistant bacteria. Lower gold concentrations, which corresponded well with the concentration from the kinetic rate, provided a selective pressure for the selection of metal-resistant organisms while retaining the overall diversity. In conclusion, biogeochemical gold cycling directly influences bacterial communities on gold particles, thereby contributing to a continuum of particle transformation.
AB - Bacteria catalyze the dissolution and re-precipitation of gold, thereby driving the biogeochemical cycle of gold. Dissolution of gold/silver and re-precipitation of gold transforms gold particles by increasing gold purity. While soluble gold complexes are highly cytotoxic, little is known about how gold cycling affects bacterial communities residing on gold particles. Micro-analysis of gold particles obtained from Western Australia revealed porous textures and aggregates of pure gold nanoparticles, attributable to gold dissolution and re-precipitation, respectively. By interpreting structure and chemistry of particles, the kinetics of gold biogeochemical cycling at the site was estimated to be 1.60 × 10-9 M year-1. Bacterial communities residing on particles were composed of Proteobacteria (42.5%), Bacteroidetes (20.1%), Acidobacteria (19.1%), Firmicutes (8.2%), Actinobacteria (3.7%) and Verrucomicrobia (3.6%). A bacterial enrichment culture obtained from particles contained a similar composition. Exposure of enrichments to increasing concentrations of soluble gold decreased community diversity and selected for metal-resistant bacteria. Lower gold concentrations, which corresponded well with the concentration from the kinetic rate, provided a selective pressure for the selection of metal-resistant organisms while retaining the overall diversity. In conclusion, biogeochemical gold cycling directly influences bacterial communities on gold particles, thereby contributing to a continuum of particle transformation.
KW - bacteria
KW - bio-mineralisation
KW - biofilms
KW - geomicrobiology
KW - gold
KW - placer
UR - http://www.scopus.com/inward/record.url?scp=85068198580&partnerID=8YFLogxK
U2 - 10.1093/femsec/fiz078
DO - 10.1093/femsec/fiz078
M3 - Article
C2 - 31132100
AN - SCOPUS:85068198580
SN - 0168-6496
VL - 95
JO - FEMS Microbiology Ecology
JF - FEMS Microbiology Ecology
IS - 7
M1 - fiz078
ER -