Plastic Packaging Destroyed By Superbugs – New Threat To PET Products Found In Kyoto Waste

Plastic Packaging Destroyed By Superbugs – New Threat To PET Products Found In Kyoto Waste: Have you ever wondered what would happen if the PET bottles used to store water and carbonated drinks could be degraded by bugs. Think of the mess in the fridge. Well it has started to happen in Japan. The “non-biodegradable” plastic PET bottle, can now be eaten by bacteria. We only created this inert plastic 70 years ago and the bacterium Ideonella sakaiensis can already eat it! Should we reinvent glass?

A Thing Of The Past? The PET bottle - already the target of naturally occurring superbugs
A Thing Of The Past? The PET bottle – already the target of naturally occurring superbugs

Those of us who have worked with microbes are well aware of their powerful potential to adapt to new environments. Nearly 40 years ago I carried out research on Enterococcus in the Bacteriology Department at Manchester University Medical school. My dissertation? Well these little organisms that live in the human gut were able to transmit little pieces of genetic information between one another during sex (or ‘conjugation’ as bacteria prefer to call it). This genetic information (small circular pieces of DNA called plasmids) contained the genes for multiple antibiotic resistance.

When humans have sex they sometimes share sexually transmitted diseases with one another. When bacteria have sex they can pass on things that are much more useful – like immunity to the powerful antibiotics we use to try and kill them. These are the same antibiotics we feed in abundance to our cows, sheep, pigs and chickens – and guess where the plasmids with antibiotic resistance probably originated? Considering their intelligent application of sex it is hardly surprising that there are a lot more bacteria in the world than people (in fact 90% of the cells in our ‘own’ bodies are microbes!).

Enterococcus faecalis (guess where it lives?) about to have twins
My old friend Enterococcus faecalis (guess where it lives?) about to give birth to twins

Due to my familiarity with bacterial ingenuity I was not surprised when on March 11th 2016 researchers in Japan announced that they had isolated a strain of bacteria that eats PET plastic. They named this PET eater Ideonella sakaiensis. It was discovered by Shosuke Yoshida and co-workers at the Kyoto Institute of Technology using samples taken from the soil and waste water around Japanese plastics recycling plants.

I remember from my own time living in Japan (30 years ago) that this nation was one of the first to seriously embrace plastics recycling so presumably the local bugs have had a bit longer to evolve the necessary enzymes. However, in evolutionary terms, this is an incredibly short period of time to develop new protein based enzyme systems. In this case the enzymes can break down a man made plastic that did not exist over 70 years ago.

The PET eating bacteria came from waste around recycling plants in Kyoto
The PET eating bacteria Ideonella sakaiensis came from waste near recycling plants in Kyoto

The newly discovered bacteria has evolved two enzymes which systematically break down the synthetic polymer that PET is made up of. You can think of this polymer as a microscopic chain of tough beads which are connected by an almost unbreakable thread. Well the bacteria is able to break down this thread separating the polymer into the individual beads (known as monomers). It then breaks down these monomers into two smaller chemical components (ethylene glycol and terephthalic acid) which it can digest using in normal biological processes to derive food and energy.

Molecular structure of the PET (Polyethylene terephthalate) used in Plastic bottles
Tough molecular structure of the PET (Polyethylene terephthalate) used in Plastic bottles

This development opens up a couple of interesting possibilities. On the one hand the bug Ideonella sakaiensis could be used itself to break down PET based plastics. There is however one snag – at 30C it takes about 6 weeks to totally break down a piece of plastic the size of a finger nail. The second possibility involves genetic engineering techniques. The genes which contain the genetic information to produce the two new proteins could be isolated from this bacteria and then inserted into another faster growing bacteria like E.coli.

This idea of inserting a ‘foreign’ gene into a different bacteria is hardly new. It is not that dissimilar to the approach I used many years ago when transferring my plasmids for antibiotic resistance. However today it is possible to use special gene ‘cut and pasteenzymes to specifically place a new gene into a bacteria’s chromosome (typical enzymes used are called ‘restriction endonucleases‘). Rather than my primitive system requiring bacterial sex the modern approach uses different carrier (vector) systems to get the genes (DNA) into the microbes. For example they can use viruses (bacteriophages) that infect bacteria by injecting their DNA into them. Molecular geneticists add the foreign gene to the viruses own DNA so they are injected into the bacteria together.

Bacteriophage used by molecular biologists to inject genes into Bacteria
Bacteriophage used by molecular biologists to inject genes into Bacteria. This virus lands on the bacteria and then ‘squirts’ its DNA into it.

The scientific community is quite excited by the prospects of harnessing microbial ingenuity to help us clear some of the rubbish that we ourselves have created through overuse of plastics. However I think one point has been overlooked by those trying to make use of this rapid evolutionary development. One of the reasons we started using plastics in place of materials like wood, cardboard and paper was their inertness. With plastic bottles and films people did not have to think about the shelf life of the packaging because usually the contents go off much quicker.

However in a world in which bugs can now break down our plastics products it may not be long before people start to discover their packaging is not as inert as they thought. Although Ideonella sakaiensis can take about 6 weeks to break down a small piece of plastic this is just the beginning. As a result of evolutionary ‘survival of the fittest‘ – more efficient plastic eating bacteria will quickly evolve. Soon those PET water bottles on the shelf could start leaking after just a few weeks. Through our thoughtless overuse of plastics (as with antibiotics) we have potentially destroyed the usefulness of what was an incredibly useful and hygienic packaging material. Watch this space!

Chris Duggleby

Look out for the bugs - PET is not just used for bottles (applications include textiles, films engineering plastics)
Look out for the bugs – PET is not just used for bottles (applications include films, engineering plastics and textiles – like the main sail on this boat)

The original paper about the discovery of this microbe “A bacterium that degrades and assimilates poly(ethylene terephthalate)” published in Science on March 11th 2016 by Shosuke Yoshida et al can be found using the link here.

Chris Duggleby started his scientific career studying Bacteriology and Virology at the Manchester University Medical School. From there he went on to spend over 35 in the chemicals and oil industries which included setting up a polymers research and development group in Geneva, Switzerland for a major international chemicals company. Following an MBA from Warwick University he went on to lead a number of international manufacturing and marketing operations in the Chemicals, Plastics and Oil industries. This included being the founding President of Formosa BP Chemicals Corporation in Asia. His work involved living and working in Europe, Asia, the USA, the Middle East, and Russia. More recently he was invited to take on a senior leadership position in the Audit Department of the BP International Oil Group. Here he used his global change and risk management experience to help the group reshape its management structures and processes following a major environmental disaster in the Gulf of Mexico. He has now retired to focus on writing about risk management and producing music in his studios near London, in the Alps and Cape Town. If you are interested in risk management check out his or (management of change) sites. He has also recently launched the site.

If you found this article interesting please consider taking a look at some of his other recent reports on similar subjects.

Just click on the titles below:

…starting with some more serious stuff…

3rd March 2016 Using Gene Drives To Change Mosquito Sex In Fight Against Zika, Dengue and Malaria

1st March 2016 Ladies – upto half a satisfying sexual event per month but risk of side effects from “Pink Viagra” Flibanserin (“Addyi”)

14th Feb 2016 Breast CancerHow Blind People Use Their Enhanced Tactile Sensitivity to Save the Lives Of Women With Tumours

3rd Feb 2016 Zika Infection Spread By Sex In Dallas – Earlier Sexual Transmission In Colorado – Detailed Symptoms 

1st Feb 2016 Sexual Competition Between Women – Ovulation Can Be Seen In The Face

31st Jan 2016  Bed Bugs – Insecticide Resistance – Arbovirus Transmission – Zika and Microcephy

19th Jan 2016 ZIKA Virus Epidemic  – Health Warning – Pregnant women should postpone travel to affected areas – Including Brazil 

17th Jan 2016 Bubonic Plague Special – Lice – Hosts for The Black Death Bug

13th Jan 2016 Kill Head Lice In A Day With The Newly Developed Plasma Nitcomb From The German Fraunhofer Institute

8th Jan 2016 Cancer from Handbags, Shoes and Gloves – Allergic Reactions to Jewellery – German Institute Identifies Excessive Chromium 6 and Nickel Levels

26th July 2015 Poison in your Washing Machine: Allergic Contact Dermatitis from Laundry Detergents, Softeners, Conditioners and Whiteners

17th October 2015: Health Risk: Vitamin and antioxidant supplements help cancer cells become malignant – latest research from Texas

31st May 2015: German Concern about Potentially Carcinogenic Aromatic Hydrocarbons in Cosmetics  

29th December 2012: Spreading diarrhea and vomit through the washing machine– The Norovirus propagator in our kitchen

and here are some fun reports…

9th March 2016: Penis Ring Emergency – German Fire Fighters Rescue Man From Painful 13 Cock Ring Torture: Vorsprung durch Technik and erectile dysfunction

4th March 2016: Dachau Industry Park Evolves From Concentration Camp To Nudist Wellness Club (Brothel)

21st June 2015: Bio-undies: Guilt free Passion with ‘Easy Emma’ and ‘Loose Harry’and Getting Rid of Garden Snails with Rent-a-Duck

4th March 2015: Hamburg Reeperbahn (St. Pauli): Germans install walls that urinate on passers-by

17th April 2014: Niche On-line Dating Services (Specialities: Herpes, Thrush and Genital Warts)

18th March 2014: Germany and Finland Joint Investigation: New Case of Sexual Cannibalism Including Self-mutilation (Castration) During Intercourse.

18th August 2012: How Bavarians and Austrians use their middle finger – Fingerhakeln: a men-only sport (did Arnold Schwarzenegger start training this way?).

You can also find some of my more humorous reports in the Alpine Press section of this site using the link here.


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