Contribution of Extracellular Polymeric Substances from Shewanella sp. HRCR-1 Biofilms to U(VI) Immobilization

Journal Article · Sun Jun 05 00:00:00 EDT 2011 · Environmental Science & Technology, 45(13):5483-5490

DOI:https://doi.org/10.1021/es200095j· OSTI ID:1023177

Cao, Bin; Ahmed, B; Kennedy, David W; Wang, Zheming; Shi, Liang; Marshall, Matthew J; Fredrickson, Jim K; Isern, Nancy G; Majors, Paul D; Beyenal, Haluk

The goal of this study was to quantify the contribution of extracellular polymeric substances (EPS) in U(VI) immobilization by Shewanella sp. HRCR-1. Through comparison of U(VI) immobilization using cells with bound EPS (bEPS) and cells without EPS, we showed that i) bEPS from Shewanella sp. HRCR-1 biofilms contributed significantly to U(VI) immobilization, especially at low initial U(VI) concentrations, through both sorption and reduction; ii) bEPS could be considered as a functional extension of the cells for U(VI) immobilization and they likely play more important roles at initial U(VI) concentrations; and iii) U(VI) reduction efficiency was found to be dependent upon initial U(VI) concentration and the efficiency decreased at lower concentrations. To quantify relative contribution of sorption and reduction in U(VI) immobilization by EPS fractions, we isolated loosely associated EPS (laEPS) and bEPS from Shewanella sp. HRCR-1 biofilms grown in a hollow fiber membrane biofilm reactor and tested their reactivity with U(V). We found that, when in reduced form, the isolated cell-free EPS fractions could reduce U(VI). Polysaccharides in the EPS likely contributed to U(VI) sorption and dominated reactivity of laEPS while redox active components (e.g., outer membrane c-type cytochromes), especially in bEPS, might facilitate U(VI) reduction.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1023177
• Report Number(s): PNNL-SA-77088; ESTHAG; 34942; 42318; KP1702030; TRN: US201118%%480
• Journal Information: Environmental Science & Technology, 45(13):5483-5490, Vol. 45, Issue 13; ISSN 0013-936X
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
CYTOCHROMES
EFFICIENCY
FIBERS
FUNCTIONALS
MEMBRANES
POLYSACCHARIDES
SORPTION
Extracellular Polymeric Substances
Shewanella
carboxyl
phosphoryl
amide
Synechococcus elongates
Citrobacter sp.
Acidithiobacillus ferrooxidans
Myxococcus xanthus
Pseudomonas stutzeri DSM 5190
Environmental Molecular Sciences Laboratory