Diffusion in biofilms respiring on electrodes

Journal Article · Thu Nov 15 04:00:00 EST 2012 · Energy and Environmental Science

DOI:https://doi.org/10.1039/C2EE23394K· OSTI ID:1094935

Renslow, Ryan S. ^[1]; Babauta, Jerome T. ^[1]; Majors, Paul D. ^[2]; Beyenal, Haluk ^[1]

---

1. Washington State Univ., Pullman, WA (United States)
2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

The goal of this study was to measure spatially and temporally resolved effective diffusion coefficients (De) in biofilms respiring on electrodes. Two model electrochemically active biofilms, Geobacter sulfurreducens PCA and Shewanella oneidensis MR-1, were investigated. A novel nuclear magnetic resonance microimaging perfusion probe capable of simultaneous electrochemical and pulsed-field gradient nuclear magnetic resonance (PFG-NMR) techniques was used. PFG-NMR allowed for noninvasive, nondestructive, high spatial resolution in situ De measurements in living biofilms respiring on electrodes. The electrodes were polarized so that they would act as the sole terminal electron acceptor for microbial metabolism. We present our results as both two-dimensional De heat maps and surface-averaged relative effective diffusion coefficient (Drs) depth profiles. We found that (1) Drs decreases with depth in G. sulfurreducens biofilms, following a sigmoid shape; (2) Drs at a given location decreases with G. sulfurreducens biofilm age; (3) average De and Drs profiles in G. sulfurreducens biofilms are lower than those in S. oneidensis biofilms—the G. sulfurreducens biofilms studied here were on average 10 times denser than the S. oneidensis biofilms; and (4) halting the respiration of a G. sulfurreducens biofilm decreases the De values. Density, reflected by De, plays a major role in the extracellular electron transfer strategies of electrochemically active biofilms.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1094935
• Report Number(s): PNNL-SA--94190; 34744; 47495; 400403309
• Journal Information: Energy and Environmental Science, Journal Name: Energy and Environmental Science Journal Issue: 2 Vol. 6; ISSN 1754-5692
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
BACTERIAL NANOWIRES
CONFOCAL MICROSCOPY
DESALINATION CELL
ELECTRICAL-CONDUCTIVITY
ELECTROACTIVE BIOFILMS
Environmental Molecular Sciences Laboratory
GEOBACTER-SULFURREDUCENS BIOFILMS
MAGNETIC-RESONANCE
MICROBIAL FUEL-CELLS
SHEWANELLA-ONEIDENSIS MR-1
WASTE-WATER TREATMENT