The latest discoveries in ‘plastic-eating microbes’

“Working on harnessing the ability of tiny microscopic bugs to break down the stubborn material.”

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The science and food media have been reporting a tasty tale these last couple of days:

Plastic Waste Can Be Transformed Into Vanilla Flavoring | Smart News | Smithsonian Magazine

Bacteria: a tasty solution to the plastic problem?

As covered by the Daily Mail:

Ice cream with a side of trash: Scientists discover method to genetically engineer E. coli to turn discarded plastic into vanilla flavoring

Scientists have figured out a way to transform plastic trash into vanilla flavoring, offering a tasty solution to a growing environmental crisis.

Researchers at the University of Edinburgh genetically engineered E. coli bacteria — yes, the stuff that causes food poisoning — to treat polyethylene terephthalate (PET), a common synthetic polymer found in water bottles, polyester clothing, car parts, packaging, electronics and more.

Enzymes from the bacteria convert the PET into vanillin, the compound that gives vanilla its yummy smell and taste..

The global plastic waste crisis is now recognized as one of the most pressing environmental issues facing our planet, prompting urgent calls for new technologies to enable a circular plastics economy,’ biologists Joanna Sadler and Stephen Wallace wrote in the journal Green Chemistry
 

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Another story which has captured the world’s media in the last day or two is what lurks in bovine stomachs – with the Guardian reporting:

Study suggests bacteria in cow’s stomach can break down plastic

Scientists find micro-organisms from the bovine stomach have ability to degrade polyesters in lab setting

Since the 1950s, more than 8bn tonnes of plastic have been produced – equivalent in weight to 1 billion elephants – driven predominantly by packaging, single-use containers, wrapping and bottles. As a result, plastic pollution is all-pervasive, in the water and in the air, with people unwittingly consuming and breathing microplastic particles. In recent years, researchers have been working on harnessing the ability of tiny microscopic bugs to break down the stubborn material.

There are existing microbes that are able to degrade natural polyester, found for example in the peels of tomatoes or apples. Given that cow diets contain these natural polyesters, scientists suspected the bovine stomach would contain a cornucopia of microbes to degrade all the plant material.

To test that theory, Dr Doris Ribitsch, of the University of Natural Resources and Life Sciences in Vienna, and her colleagues procured liquid from the rumen, a compartment of a cow’s stomach, from a slaughterhouse in Austria…

Study suggests bacteria in cow’s stomach can break down plastic | Plastics | The Guardian

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This is from the scientific paper itself:

Together Is Better: The Rumen Microbial Community as Biological Toolbox for Degradation of Synthetic Polyesters

Microorganisms, like bacteria and fungi, are becoming an emerging resource for the development of eco-sustainable plastic degradation and recycling processes. 

… in the last two decades, the concept of bio-economy motivated the scientific community to focus on production of bio-based and/or biodegradable polyesters and/or technologies for microbial or enzymatic recycling. Thereby, the application of highly specific enzymes allows for a stepwise recovery of highly valuable building blocks from blended plastics or mixed waste streams. Previous studies from our group and others have demonstrated the potential of enzymes for the hydrolysis of poly(ethylene terephthalate) (PET), the most important synthetic polyester used in numerous applications including textiles and packaging.

Ruminants are a well-studied group of herbivorous mammals. They have evolved a forestomach, the rumen (or more precisely the reticulorumen), which is a large chamber (50–100 L capacity in adult cattle) where the ingested feed is subjected to microbial degradation before the real animal digestion.

As a consequence, the main objective of this study therefore was to explore the microbial community of the rumen from ruminant animals regarding polyester-degrading enzyme activities.

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And, in fact, there are lots of other ‘plastic-eating’ microbes out there being discovered, with these reports only from the last couple of days:

Could plastic-eating microbes take a bite out of the recycling problem? | Science | AAAS

New microbial enzyme breaks down lignin for less expensive biofuels, bioproducts – Green Car Congress

   
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