Sorption versus Biomineralization of Pb(II) within Burkholderia cepacia Biofilms

Journal Article · Wed Jan 15 04:00:00 EST 2003 · Environmental Science and Technology, 37((2)):300-307

DOI:https://doi.org/10.1021/es025972g· OSTI ID:15004985

Templeton, Alexis S; Trainor, T P; Spormann, Alfred M; Newville, Mathew; Sutton, Steven R; Dohnalkova, Alice; Gorby, Yuri A; Brown, Gordon E

X-ray spectroscopy measurements have been combined with macroscopic uptake data and transmission electron microscopy (TEM) results to show that Pb(II) uptake by Burkholderia cepacia is due to simultaneous sorption and biomineralization processes. X-ray microprobe mapping of B. cepacia biofilms formed on -Al2O3 surfaces shows that Pb(II) is distributed heterogeneously throughout the biofilms because of the formation of Pb "hot spots". EXAFS data and TEM observations show that the enhanced Pb accumulation is due to the formation of nanoscale crystals of pyromorphite (Pb5(PO4)3(OH)) adjacent to the outer-membrane of a fraction of the total population of B. cepacia cells. In contrast, B. cepacia cell suspensions or biofilms that were heat-killed or pretreated with X-rays do not form pyromorphite, which suggests that metabolic activity is required. Precipitation of pyromorphite occurs over several orders of magnitude in [H+] and [Pb] and accounts for approximately 90% of the total Pb uptake below pH 4.5 but only 45-60% at near-neutral pH because of the formation of additional Pb(II) adsorption complexes. Structural fits of Pb LIII EXAFS data collected for heat-treated cells at near-neutral pH suggest that Pb(II) forms inner-sphere adsorption complexes with carboxyl functional groups in the biofilms.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 15004985
• Report Number(s): PNNL-SA-38221; 2245; KP1704020
• Journal Information: Environmental Science and Technology, 37((2)):300-307, Journal Name: Environmental Science and Technology, 37((2)):300-307 Journal Issue: 2 Vol. 37; ISSN ESTHAG; ISSN 0013-936X
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
59 BASIC BIOLOGICAL SCIENCES
ADSORPTION
BACTERIA
BIOCONVERSION
DENSITY FUNCTIONAL METHOD
Environmental Molecular Sciences Laboratory
LEAD
PRECIPITATION
Sorption
biomineralization
Burkholderia
biofilms
UPTAKE