E-Waste Recycling with Microbes

Delftia acidovorans

Did you Know?

  • Delftia acidovorans refines gold from cyanide soluions.
  • The microbe produces delftibactin, which is a chemical that makes gold to precipitate as nanoparticles.
  • D. acidovorans only extracts 18% of the gold as nanoparticles, so more research is needed.

Questions to think about and answer
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….

  • Can we genetically modify Delftia acidovorans to increase its efficiency?
  • Can we culture enough D. acidovorans to produce an ample amount of delftibactin so gold can be extracted quicker and in higher amounts ?

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2013.igem.org ›
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What other ways could electronic waste be recycled?

Bioleaching

  • A procedure to extract metals using living organsims.

Bacteria to consider:

Chromobacterium violaceum
  • The bacterium produces an antimicrobial agent known as violacein.
  • It has the ability to recover many metals from massive quantities of electrical waste.
Gluconobacter oxydans
  • The microbe produces gluconic acid which surrounds and binds to rare earth elements by forming a cage around the element.
  • The rare element can then be released by changing the pH or adding a solvent.
Cupriavidus metallidurans
  • The microbe is used as a sponge to absorb gold.
  • In an experiment, 85 to 90% of the gold was recovered.
  • It may be more effective and easier to collect gold using C. metallidurans than D. acidovorans.

Questions to think about and answer:
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  • What are the differences and similarities between Delftia acidovorans and Cupriavidus metallidurans?
  • Why is it easier to collect gold from Cupriavidus metallidurans?

Activity

Compare and contrast the different types of bacteria, and how they can be used to recycle electronic waste.
ncbi.nlm.nih.gov ›
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Pyrometallurgy

  • A method in which high temperatures are needed to heat electronic waste.
  • The temperature could reach more than 1000 degrees celsius, ~1832 Fahrenheit.
  • During the process, toxic gases are released into the atmosphere.

It requires a lot of energy.

Hydrometallurgy

  • A method in which chemicals, such as acids, are used to filter metals.
  • During the process, toxic gases are released.

Activity: Your opinion

Based on the information above, which method of e-waste recycling is the most effective, and which method is the least effective? Why? (bioleaching, pyrometallurgy, or hydrometallurgy)

Why are companies not using microbes to recycle e-waste?

  • It does not float their boat. If it is not profitable, companies are less likely to recycle products that have low amounts of valuable materials; companies are more likely to recycle a phone than a hairdryer.
  • The lack of efficiency in recycling precious metals.
  • The process of bioleaching is slow.
  • During the process of bioleaching, toxic chemicals may be produced.
Despite the method of using microbes to recycle e-waste seems less efficient and not profitable in the current time, in the future with more advanced technology, this might be an alternative solution to the e-waste management problems. It can be done with efficiency and have less of an impact on human health and the environment.

Connect the dots:

Read this article about EV Battery Recycling
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, then answer a few questions:
1. How much e-waste ends up in landfills each year?
2. How are lithium-ion batteries recycled?
3. How can bioleaching improve the recycling of electric vehicle batteries?
4. Discuss how using bioleaching and microbes to recycle metals can reduce the carbon footprint of electronic waste.

Bacteria – yes, bacteria – could be the key to recycling EV batteriesBacteria could help recycle EV battery parts through a process called "bioleaching."

thenextweb.com ›
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