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← This bacteria eats plastic

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Showing Revision 8 created 05/28/2019 by Oliver Friedman.

  1. Plastics: you know about them,
    you may not love them,

  2. but chances are
    you use them every single day.
  3. By 2050, researchers estimate
  4. that there will be more plastic
    in the ocean than fish.
  5. Despite our best efforts,

  6. only nine percent of all plastic we use
    winds up being recycled.
  7. And even worse,
  8. plastic is incredibly tough and durable
  9. and researchers estimate
  10. that it can take anywhere
    from 500 to 5,000 years
  11. to fully break down.
  12. It leaches harmful chemical contaminants
    into our oceans, our soil,
  13. our food, our water, and into us.
  14. So how did we wind up
    with so much plastic waste?

  15. Well, it's simple.
  16. Plastic is cheap, durable,
    adaptable, and it's everywhere.
  17. But the good news is
  18. there's something else that's cheap,
    durable, adaptable and everywhere.
  19. And my research shows
    it may even be able to help us
  20. with our plastic pollution problem.
  21. I'm talking about bacteria.

  22. Bacteria are microscopic living beings
    invisible to the naked eye
  23. that live everywhere,
  24. in all sorts of diverse
    and extreme environments,
  25. from the human gut, to soil, to skin,
  26. to vents in the ocean floor, reaching
    temperatures of 700 degrees Fahrenheit.
  27. Bacteria live everywhere,
  28. in all sorts of diverse
    and extreme environments.
  29. And as such, they have to get
    pretty creative with their food sources.
  30. There's also a lot of them.
  31. Researchers estimate that there are
    roughly five million trillion trillion --
  32. that's a five with 30 zeros after it --
    bacteria on the planet.
  33. Now, considering that we humans produce
  34. 300 million tons of new plastic each year,
  35. I'd say that our plastic numbers
  36. are looking pretty
    comparable to bacteria's.
  37. So, after noticing this

  38. and after learning
    about all of the creative ways
  39. that bacteria find food,
  40. I started to think:
  41. could bacteria in
    plastic-polluted environments
  42. have figured out
    how to use plastic for food?
  43. Well, this is the question that I decided
    to pursue a couple of years ago.
  44. Now, fortunately for me,
  45. I'm from one of the most
    polluted cities in America,
  46. Houston, Texas.
  47. (Laughs)

  48. In my hometown alone,

  49. there are seven EPA-designated
    Superfund sites.
  50. These are sites that are so polluted,
  51. that the government has deemed
    their cleanup a national priority.
  52. So I decided to trek around to these sites
  53. and collect soil samples
    teeming with bacteria.
  54. I started toying with a protocol,
  55. which is fancy science talk for a recipe.
  56. And what I was trying to cook up
    was a carbon-free media,
  57. or a food-free environment.
  58. An environment without the usual
    carbons, or food,
  59. that bacteria, like us humans,
    need to live.
  60. Now, in this environment,

  61. I would provide my bacteria
    with a sole carbon, or food, source.
  62. I would feed my bacteria
    polyethylene terephthalate,
  63. or PET plastic.
  64. PET plastic is the most widely produced
    plastic in the world.
  65. It's used in all sorts
    of food and drink containers,
  66. with the most notorious example
    being plastic water bottles,
  67. of which we humans currently go through
    at a rate of one million per minute.
  68. So, what I would be doing,
  69. is essentially putting my bacteria
    on a forced diet of PET plastic
  70. and seeing which, if any,
    might survive or, hopefully, thrive.
  71. See, this type of experiment
    would act as a screen

  72. for bacteria that had adapted
    to their plastic-polluted environment
  73. and evolved the incredibly cool
    ability to eat PET plastic.
  74. And using this screen,
  75. I was able to find some bacteria
    that had done just that.
  76. These bacteria had figured out
    how to eat PET plastic.
  77. So how do these bacteria do this?

  78. Well, it's actually pretty simple.
  79. Just as we humans digest carbon or food
    into chunks of sugar
  80. that we then use for energy,
  81. so too do my bacteria.
  82. My bacteria, however, have figured out
    how to do this digestion process
  83. to big, tough, durable PET plastic.
  84. Now, to do this,
    my bacteria use a special version

  85. of what's called an enzyme.
  86. Now, enzymes are simply compounds
    that exist in all living things.
  87. There are many different types of enzymes,
  88. but basically, they make
    processes go forward,
  89. such as the digestion of food into energy.
  90. For instance, we humans
    have an enzyme called an amylase
  91. that helps us digest
    complex starches, such as bread,
  92. into small chunks of sugar
    that we can then use for energy.
  93. Now, my bacteria have
    a special enzyme called a lipase
  94. that binds to big, tough,
    durable PET plastic
  95. and helps break it
    into small chunks of sugar
  96. that my bacteria can then use for energy.
  97. So basically,
  98. PET plastic goes from being
    a big, tough, long-lasting pollutant
  99. to a tasty meal for my bacteria.
  100. Sounds pretty cool, right?
  101. And I think, given the current scope
    of our plastic pollution problem,

  102. I think it sounds pretty useful.
  103. The statistics I shared with you
  104. on just how much plastic waste
    has accumulated on our planet
  105. are daunting.
  106. They're scary.
  107. And I think they highlight
  108. that while reducing, reusing
    and recycling are important,
  109. they alone are not going to be enough
    to solve this problem.
  110. And this is where I think bacteria
    might be able to help us out.
  111. But I do understand
    why the concept of bacterial help

  112. might make some people a little nervous.
  113. After all, if plastic is everywhere
    and these bacteria eat plastic,
  114. isn't there a risk of these bacteria
    getting out in the environment
  115. and wreaking havoc?
  116. Well, the short answer is no,
    and I'll tell you why.
  117. These bacteria are already
    in the environment.
  118. The bacteria in my research
    are not genetically modified frankenbugs.
  119. These are naturally occurring bacteria
  120. that have simply adapted
    to their plastic-polluted environment
  121. and evolved the incredibly gnarly
    ability to eat PET plastic.
  122. So the process of bacteria eating plastic
    is actually a natural one.

  123. But it's an incredibly slow process.
  124. And there remains a lot of work to be done
  125. to figure out how to speed up
    this process to a useful pace.
  126. My research is currently
    looking at ways of doing this
  127. through a series of UV,
    or ultraviolet, pretreatments,
  128. which basically means
    we blast PET plastic with sunlight.
  129. We do this because sunlight
    acts a bit like tenderizer on a steak,
  130. turning the big, tough,
    durable bonds in PET plastic
  131. a bit softer and a bit easier
    for my bacteria to chew on.
  132. Ultimately, what my research hopes to do

  133. is create an industrial-scale
    contained carbon-free system,
  134. similar to a compost heap,
  135. where these bacteria can thrive
    in a contained system,
  136. where their sole food source
    is PET plastic waste.
  137. Imagine one day being able to dispose
    of all of your plastic waste
  138. in a bin at the curb
  139. that you knew was bound for a dedicated
    bacteria-powered plastic waste facility.
  140. I think with some hard work
    this is an achievable reality.
  141. Plastic-eating bacteria is not a cure-all.

  142. But given the current statistics,
    it's clear that we humans,
  143. we could use a little help
    with this problem.
  144. Because people,
  145. we possess a pressing problem
    of plastic pollution.
  146. And bacteria might be
    a really important part of the solution.
  147. Thank you.

  148. (Applause)