Electrochemical activity of Geobacillus sp. strain WSUCF1 under
thermophilic conditions
Namita Shrestha1, Shailabh Rauniyar2, Rajesh Sani2, and Venkataramana Gadhamshetty1*
1Civil
and Environmental Engineering, South Dakota School of Mines and Technology, 2Chemical & Biological Engineering, South Dakota School of Mines and Technology,
* Author to whom all correspondence should be addressed to: E-mail: [email protected]; Tel: +1-605-394-1997
Objectives
The overarching goal of the project is to investigate the
extracellular respiratory capabilities of extremophiles isolated
from the Sanford Underground Research Facility (SURF)
extremophiles under thermophilic conditions. The extremophiles
will be used to treat in-situ resources (solid wastes (SOWs))
generated during long-term space missions.
Materials
Current response
Reactor: Three electrode electrochemical cell
Working electrode : Glassy carbon
Counter electrode: Platinum Counter
Reference electrode: Ag/AgCl/KCl reference
Electrochemical Work station : Gamry Ref 3000
Bacterial Strain : WSUCF1
Temperature: 60 degree Celsius
800
Current (nA)
1
Glucose
Control
Cornstover
600
400
200
0
0
Electron Bacterial
donor
Strain
Duration
Electro chemical
Test
Temp
Purpose
10 d
EIS ,CV, Chronoamperometry,
DPV
60 oC
Specific objectives:
• Develop and validate a bioelectrochemical module (BEM)
that produces electricity as a product from treatment of
organic wastes and synthetic polymers from manned space
missions.
TEST #3
WSUCF1
None
20
None
10 d
25k
30k
To monitor biofilm growth
EIS ,CV, Chronoamperometry, As a control for Glucose substrate
DPV
o
60 C
EIS ,CV, Chronoamperometry,
DPV
60 oC
80
Glucose
Cornstover
Control
To study redox species
To measure the current
Corn
TEST #2
stover
20k
Electrochemical Impedance
- Phase Angle (degrees)
WSUCF1
15k
Fig. 2. Chrono-amperometry scan response for all substrates
To study biofilm impedance
TEST #1 Glucose
10k
Time (s)
Experimental plan
TEST
5k
60
40
20
Medium
frequency
Low
frequency
As a control for WSUCF1
High
frequency
0
10-2
10-1
100
101
102
103
104
frequency (Hz)
• Understand microgravity (μg) effects on exoelectrogenic
behavior and biofilm formation potential of extremophiles
during space flight.
Fig. 3. Bode phase angle plot from the frequency 0.01 Hz to 10 kHz
Experimental setup
Cyclic Voltammetry
30
Cornstover
Glucose
Control
Potentiostat connection
wires
Current (A)
20
Data acquisition
Heated water circulating
bath
Gamry Ref 3000
Potentiostat
10
0
-10
-20
-1.0
Outlet
-0.5
0.0
0.5
1.0
Potential (V)
Hot water inlet
Fig. 4. Cyclic voltammetry curve at scan rate of 1mv/s
Conclusion
Introduction
Representative Extremophile: WSUCF1
The current study is a first to investigate feasibility of using
extremophile Geobacillus sp. strain WSUCF1 for enabling a
thermophilic (> 60°C) operation of bioelectrochemical systems
(BESs).
Objectives:
• To evaluate the ability of WSUFC1 to utilize glassy carbon
electrode as the electron acceptor
• Measure the voltammetric and impedance characteristics of
WSUCF1 biofilm
Preliminary Results
Current Density
50
40
Current density (mA/m2)
The NASA Science and Mission Systems Office has developed
the “In-Situ Resource Utilization” program with the intent to
develop technologies that obtain energy by using in-situ
resources during manned space-missions, e.g., efforts to
capture asteroids, explore Mars, establish, and use an
inhabitable facility on the Moon’s surface. Examples of in-situ
resources include solar radiation in space and the solid wastes
generated during a lunar exploratory mission.
1) Representative Extremophile
• WSUCF1→responding to the electrochemical test
• Maximum current density using Glucose :45mA/m2
• Ability to use complex carbon substrates including corn
stover
2) Work in Progress
• Test range of extremophiles
• Evaluate photo-assisted polymer degradation
• Test graphene anode developed
• Stacks for amplified power rating
30
Acknowledgement: This study was in part supported by NASA
(# NNX13AB25A) and NSF (#1454102)
20
10
Reference:
0
1
2
3
Glucose
4
5
6
Time (d)
Cornstover
7
8
9
Control
Fig. 1. Current density variation in different substrate with time elapsed
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