Biocides and Bacteria
Kansas City, MO
Flight Experiment, Mission 6 to ISS
Team Cosmic Supernova
CO-PRINCIPAL INVESTIGATORS:
Eamon Shaw
Nicole Ficklin
Holden O’Keefe
St. Peter’s School
Diocese of Kansas City – St. Joseph
Teacher Facilitator:
Robert J. Jacobsen, St. Peter’s School
Abstract
The investigation aimed to determine the effects of the antibacterial agent liquid
iodine on Escherichia coli bacteria in microgravity as compared to its effects in the gravity of
Earth. The experiment was conducted aboard the International Space Station (ISS), with two
controls on Earth. After testing, the researchers found that their hypothesis was proven:
antibacterial agents in microgravity are shown to be less effective, as a result of microgravity
inhibiting antibacterial power and/or the greater resilience of bacteria in a microgravity
environment.
Statement of the Problem
If an outbreak of dangerous bacteria was to occur on the International Space Station, it
would need to be eliminated as quickly and completely as possible. Because of the
substantial distance between Earth and the ISS, and the complicated and extensive process
necessary to send anything to the International Space Station, a fast-acting and effective
antibacterial agent would need to be available. For these reasons, the investigators tested
the effects of liquid iodine upon Escherichia coli bacteria in microgravity.
It was hypothesized that the E. coli would not be eliminated as well in microgravity as it
would in the gravity of Earth. This is because microbes are known to reproduce faster in
microgravity, and because of the fact that microbes in space are known to have evolved
features, such as: a “column and canopy” structure not found on Earth and more biomass.
Experimental Procedure
The experiment was conducted using a Type III Fluid Mixing Enclosure (FME) that
was separated into three volumes. Volume 1 held a mixture of rehydration medium and liquid
iodine for activation and elimination of the bacteria. Volume 2 held the freeze-dried E. coli
bacteria, and Volume 3 held a glutaraldehyde solution (Grade II, 25% in distilled water) which
acted as a fixative and inhibited bacterial growth at the conclusion of the experiment.
Clamp A, separating Volumes A and B, was released five days before undocking, allowing
the E. coli and liquid iodine to interact for three days time. Clamp B was released two days
before undocking, allowing the E. coli and glutaraldehyde to interact, inhibiting bacterial
growth and terminating the experiment. Two controls were conducted in conjunction with
the investigation in microgravity: one containing iodine and one not containing iodine.
Interpretation of Data
Once samples from all three FMEs were analyzed, it was determined that the control
FME containing iodine had no living E. coli, the control FME that did not contain iodine had a
great amount of bacterial growth, and the FME that was tested aboard the ISS contained far
less living bacteria than the no-iodine FME. The living bacteria observed here were deformed
and were much smaller than the bacteria observed from the no-iodine FME, but were still
living nonetheless. This suggests that the iodine is less effective in microgravity.
A possible reason for this could be that the antibacterial properties of iodine are not
sufficient in microgravity, being that microbes are known to be more resilient in microgravity.
Also, the substances aboard the ISS had less surface contact; on Earth, gravity would pull the
substances together, allowing constant contact (and elimination), while the opposite
occurred in microgravity.
As is the case with all scientific investigations, this was determined from the results of one
test, and, of course, more tests are needed to be conducted to substantiate these findings.
CONTROL SAMPLE
WITHOUT IODINE
nbuoboui
A microscopic look at the control
sample after being conducted in
gravity with no iodine. An abundance
of E. coli can be seen, large and
healthy.
CONTROL SAMPLE
WITH IODINE
Nmlnljb lk
A microscopic look at the control
sample after being performed in
gravity with iodine. No E. coli can be
seen.
EXPERIMENTAL SAMPLE
k kh khkh
A microscopic look at the sample
after being conducted in the
microgravity of the ISS. Traces of E. coli
can be seen, though very small and
highly distorted.
Acknowledgements
Teacher Facilitator
Partner Institutions
Robert J. Jacobsen
Benjamin Banneker Charter Academy of Technology
Sponsors
aSTEAM Village
St. Peter’s School
Distribution by Air
Académie Lafayette
Overland Park Microsoft Store
Della Lamb Elementary Public Charter School
University of Kansas School of Education GEAR UP Program
Hogan Preparatory Academy Middle School
St. Peter’s School PTA
Gemini Gentlemen Homeschool Group
University of Central Missouri
Notre Dame de Sion School
Cardelia Walker Real Estate
Arrowhead Middle School
Center for the Advancement of Science in Space
Rosedale Middle School
National Center for Earth and Space Science Education
D.D. Eisenhower Middle School
Argentine Middle School
Boys and Girls Club of the Ozarks
St. Teresa’s Academy