1. Shewanella oneidensis MR1 Uptake in a Sand Column
Austin Sattler, Jianing Zhuo, Somayeh Ramezanian, and Nehal I. Abu-Lail
Gene and Linda Voiland School of Chemical Engineering and Bioengineering, WSU
Introduction
 Bacteria in sand columns can be used as
barriers to remediate contaminated sands or
provide an environmentally friendly way to
prevent soil from erosion.
 Our goal is to explore the role of pH
conditions on Shewanella oneidensis MR1
uptake in a sand column.
 We hypothesize that at neutral pH,
bacterial uptake in the sand column will be
highest compared to acidic and basic
conditions.
Methodology
Bacterial culture
• Gram negative, facultative bacteria.
• The kinetics of growth of S. oneidensis
MR-1 were followed over the course of
36 hours.
• Bacterial cells were cultivated when they
reached the late exponential phase of
growth.
Sand
• Silica sand was soaked for 24 hours prior
to each experiment.
Conclusions
• Bacterial cells were retained at a much
higher level at pH 7.12 compared to pH
3.99 or pH 10.07.
• Our findings supported our hypothesis.
• Based on our results, we expect that at
neutral pH conditions, MR1 will be
available for biofilm formation and thus
can potentially be used to enhance soil
stability and bioremediation.
References
1. Torkzaban, S., et. al (2008), Water Resour. Res., 44, W04403.
2. Beckman, M. (2009) , PNNL.
http://www.pnnl.gov/news/release.aspx?id=348.
Acknowledgements
We would like to thank:
• NSF award number 1266366 for funding
of this work.
• Dr. Haluk Beyenal for providing the
bacterial strain we are working with.
• Dr. Balasingam Muhunthan for
providing the sand we used in the study.
PNL.gov http://microbewiki.kenyon.eduIowaenvironmentalscience.org
Column experiments
• Phosphate-buffered saline (PBS) was used to control the pH of the
influent.
• Bacterial suspension was diluted to an initial optical density (OD) of 0.100
at a λ of 600 nm.
• Bacterial solution was fed to the column at 0.062 ml/s in upward laminar
flow manner.
• Effluent samples of 2 mL each were collected.
• Column dimensions, porosity, pore volume.
0
0.02
0.04
0.06
0.08
0.1
0.12
0 50 100
C/C0
Time
0
0.1
0.2
0.3
0.4
0.5
0.6
0 50 100
C/C0
Time
0
0.1
0.2
0.3
0.4
0.5
0.6
0 20 40 60 80 100
C/C0
Time
0
0.1
0.2
0.3
0.4
0.5
0 20 40 60 80 100
C/C0
Time
pH: 3.99
pH: 7.12
pH: 10.07
0
0.2
0.4
0.6
0.8
1
1.2
1 4 7 10 13
Steadystateretention
pH
0
0.5
1
1.5
2
0 5 10 15 20 25 30 35
ODat600nm
Time (Hours)
MR1
Future directions
Different kind of bacteria has different living
environment and behaviors. We are going to
study other bacterial types in the future,.
These include P. putida and L. mesenteroides.
Columnexperimentsetting
pH 4 pH 7
pH 10