I want you to imagine something for me: If you would depict the top must-see
attractions for visitors coming to Yellowstone, what would they be? I'm going
to say you're considering things like seeing an eruption of Old Faithful,
watching wildlife in Lamar Valley, or walking around the enormous rim of Grand
Prismatic, something along those lines, am I right? Okay, now how many visitors do
you think would rank seeing tiny microscopic organisms thriving in the
parks hydrothermal features as a must-see attraction? Probably not many.
A visitor might love seeing the rainbow-colored waters, but I doubt their
interests are focused on the trillions of microbial cells that come together to
form that beautiful colored mat. Well, my name is Dr. Dana Skorupa and I think
about hot spring microorganisms a lot. As a thermal biologist at Montana State
University, I spend my time trying to figure out ways to harness the cellular
machinery inside hot spring microorganisms and use them in
commercial industries which must operate at extreme conditions. You might be
asking yourself are hot springs really a good place to look for microorganisms
with beneficial uses? My answer to that question would be an emphatic yes and
here's why. If we count the number of different macro-fauna species in
Yellowstoneâthat being any organism we can see with our naked eyeâit would
total around 2,000 different species. Now let's compare that to the number of
different microbial species in just one hot spring. Here we can see there's over
5,000 different speciesâand that's just one spring! Park-wide, Yellowstone is home
to over 14,000 geothermal features. This means, high temperature habitats are the
true source of Yellowstone's biological diversity and they give us a much higher
chance of finding organisms with cool commercial applications. Okay, I want to
switch gears for just a minute and talk trash. Humans are producing enormous
amounts of plastic trashâmost of which nature can't digest. To date, humans have
produced over 300 million tons of plastic waste and of that only 8% is
annually recycled. Plastics are notoriously difficult to break down.
It can take agonizing 1,000 years for a single
plastic water bottle to biodegrade. However, back in 2016 a team of
microbiologists made a significant breakthrough. They isolated a bacteria
from a plastic recycling facility that could literally eat plastic as its food.
Sounds cool, right? Problem solved. We'll use this new microbe to recycle plastics.
Well, it's not quite that easy. See, it's actually the enzyme that's made and
produced and excreted by this organism, which gives it the ability to eat
plastic. In order for the recycling industry to use this enzyme, it must be
able to function at temperatures where the plastic begins to soften. This
softened state is where the enzyme can really burrow into the material and
effectively break it down. The rub is many plastics don't begin to soften
until they reach high temperatures, say on the order of 140 to 170 degrees
Fahrenheit. Our problem, therefore, is we have yet to discover a plastic-eating
microorganism that produces heat-stable enzymes. Hmmm... where on our planet would be
look for such an organism? You see where I'm going with this, right? Yellowstone
hot springs. Hot spring microorganisms have evolved over billions of years to
survive under extreme temperature conditions.
This means the enzymes they produce are stable at or near the boiling point of
water. Now, you might be asking yourself but why would a hot spring microbe be able
to eat plastic, there's none around in its environment? Well, all living
organisms need access to the building block of life: carbon. It turns out plants
are an easy to use carbon source for many microorganisms, including those
living in hot springs. Next time you're in the park take note of all the downed
trees, leaves, and pine needles present in the springs. To break down plant material,
some species of bacteria and fungi produce an enzyme called Cutinase.
It helps them gain access to the carbon molecules tied up in that plant biomass.
And it turns out this enzyme isn't picky; it's perfectly happy chewing on plants
or polymers like plastic. So, I'm a thermal biologist on a
treasure hunt, hoping some of Yellowstone's hot spring microorganisms
produce heat-stable enzymes that can eat plastic. To start my search, I travel to
Yellowstone and collect small volumes of mud from different springs around the
park. The mud at the bottom of the springs is where many microbes reside.
Out of the thousands of different species present in each spring, I want
ones that eat plastic. So, I culture my organisms such that plastic is the only
carbon source available. In doing this, if any microbe is able to grow it must
survive by eating the plastic. I then look for indicators of microbial growth
and material degradation. I often collect microscopic images of
the plastic surface, both before and after it's cultured alongside my hot
spring microbes. This helps me look for signs of degradation. Degraded plastics
form pits and crevices over time, and sometimes the microbes even burrow into
the material as a more effective chewing technique. I also track the
consumption and production of different gases using them as indicators that
microbes are growing. If microbes are growing in my culture they will breathe
in oxygen, just like you and me. Thus, in a closed environment like the ones I
created my laboratory cultures, oxygen levels will decrease at the same time
one of the byproducts of plastic degradation is carbon dioxide. So, through
some additional gas measurements and a little bit of math, I can figure out how
much of that plastic material is converted to carbon dioxide. Though my
research is still in its early stages, I'm hopeful that Yellowstone hot springs
âand the amazing biodiversity they houseâcan help us develop an effective industry
for recycling plastics and reducing waste pollution. Thank you!