thank you to Skillshare for sponsoring
this episode of scishow the stuff that
you flush down the toilet isn't just
waste the organic material that contains
could be used as an energy source if we
could figure out how to use it
effectively that's what scientists in
Spain might have figured out a way to do
in a new paper in the journal frontiers
in energy research they report that
purple bacteria could help us harness
that energy and reduce carbon emissions
at the same time purple bacteria or
purple phototrophic bacteria to be more
precise are a group of bacterial species
that can make their own food using
photosynthesis kind of like plants and
algae do their color which actually
ranges from red to purple comes from
pigments like carotenoids which they
used to capture light energy and while
plants use that light energy to convert
carbon dioxide and water into sugars and
oxygen purple bacteria are a lot more
flexible they can start with lots of
different ingredients and depending on
the source of carbon they start with and
environmental factors like temperature
and light intensity they can make a wide
variety of products including small
proteins and even a type of
biodegradable polyester but it's their
ability to produce hydrogen known as bio
hydrogen in this case because it comes
from living things that has scientists
excited some engineers think bio
hydrogen could be the fuel of the future
because it can produce a lot of energy
with little or no carbon emission and
the main byproduct of burning hydrogen
is water which is pretty great
unfortunately we're still working at the
best ways to produce a store and deliver
bio hydrogen and purple bacteria could
be part of the answer researchers were
able to take purple bacteria growing
naturally in wastewater and cultivate
them by shining infrared lamps on like a
sludge mix then they manipulated the
carbon and nitrogen sources they gave to
these bacteria to see which maximized
bio hydrogen production they even tried
offering them electrons by sticking one
end of a battery into the flask they
were growing in in the end two compounds
common in wastewater malic acid as a
carbon source and sodium glutamate as a
nitrogen source produced the most
hydrogen while minimizing carbon dioxide
emissions using this mixture the
bacteria produced 400 milliliters of
hydrogen gas per liter of bacterial soup
that's about enough to drive a hydrogen
powered car three meters wow that might
not seem like a lot it could add up
quickly I mean the US has to process
some 128 billion liters of wastewater a
day it would really intrigued the
researchers was that the bacteria were
able to take the extra electrons from
the battery to use up more of the carbon
they were given although that wasn't
exactly what the researchers were aiming
for it could point to a strategy for
reducing carbon emissions produced by
wastewater treatment so the research
represents important progress on the
road to converting our poop into clean
green energy or maybe purple energy why
not and speaking of clean energy last
week scientists unveiled Bionic
mushrooms that can produce electricity
and a new paper in the journal nano
letters the current they generate is
thanks to a cyanobacteria a kind of
aquatic bacteria which the researchers
3d printed onto plain ol button mushroom
caps along with a conductive graphene
ink while they aren't going to replace
your rooftop solar panels anytime soon
these Bionic mushrooms are the first
example of an engineered relationship
between different types of organisms and
maybe a glimpse at energy technologies
to come solar panels are basically an
engineer's best attempt to mimic a plant
but plants algae and bacteria that
photosynthesize are a lot better at
capturing the sun's energy than we are
cyanobacteria for example are almost a
hundred percent efficient which means
that for every photon of light they
capture they generate one electron for
comparison the best solar panels you can
buy and put on your roof are about 20%
efficient so for decades scientists have
been working on methods to use living
organisms to generate electricity more
efficiently but cyanobacteria are
aquatic and tend to be quite finicky
they don't like growing on artificial
surfaces research is behind the Bionic
mushrooms we're trying to figure out
what they could grow the bacteria on
when they realized that lots of species
of fungi partner with other organisms
apparently this dawned on them over
lunch one day because you know
scientists eat mushrooms sometimes the
team
if they could make that kind of
relationship happen so they bought some
white button mushrooms from a local
grocery store the same kind you might
pick to make it tasty batch of
stroganoff for sprinkle on your pizza
using a 3d printer and ink made of
graphene nanoribbons super tiny strips
of carbon atoms arranged in a lattice
they made a mini grid on the mushrooms
where current could flow then they 3d
printed colonies of cyanobacteria on top
in a spiral the water and nutrients
provided by the mushroom cap helped keep
the cyanobacteria alive they lived
longer on a living cap then on a silicon
version or on one killed with vinegar
and the electricity conducting ink was
able to snag some of the electrons the
live cyanobacteria produced during
photosynthesis and passed them off to
connecting wires and generating a
current when the researchers shined
light on one of these Bionic mushrooms
it generated an electrical current of
about 65 nano amps or billionths of an
amp that's not a lot it takes a current
of roughly a full amp to charge your
cell phone but the researchers are
working on tweaking this system to
produce more electricity if they could
make it more efficient or string
together lots of these mushrooms they
might be able to create a whole new kind
of solar panel but really what's
exciting about this is that it worked at
all I mean the researchers merged
cellular biology with nano engineering
to create living tech and that could
open the door to harnessing other
microbial super powers designing the
tech of the future will take a lot of
brainpower and some really clever
scientists willing to try things like 3d
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