Ice cream with a side of trash: Scientists discover method to genetically engineer E. coli to turn discarded plastic into vanilla flavoring
- Polyethylene terephthalate (PET) is found in water bottles, clothing, and more
- Some 55 million tons of this common microplastic gets thrown out each year
- Vanillin is the compound that gives vanilla its smell and taste
- Biologists were able to make vanillin from PET using a benign strain of E. Coli, the bacteria that causes food poisoning
- The process could help reduce plastic pollution and meet soaring demand for vanillin, expected to surpass 65,000 tons by 2025
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.
Some 55 million tons of PET gets thrown out each year, so new uses for it ‘would have considerable economic as well as environmental impact,’ the authors said.
PET is made of ethylene glycol and terepthalic acid, which bond to create long strands of plastic that are then cut up and melted down to make clothing, wrap and more, according to SyFy Wire.
Vanillin is an aldehyde, an organic substance made of carbon, hydrogen and oxygen.
It can be distilled naturally from vanilla beans but is more commonly synthesized from fossil fuels because it’s cheaper and they’re more readily available.
Terepthalic acid has been converted to vanillic acid before, but never into actual vanillin.
Researchers at the University of Edinburgh were able to convert plastic waste into vanillin, using enzymes produced by E. coli, offering a solution to the growing plastic pollution crisis
Sadler and Wallace theorized it could be done with enzymes from E. coli, which uses oxygen as a catalyst.
Through a five-step process, they converted the terephthalic acid from a plastic bottle into vanillin using enzymes produced by E. coli MG1655 RARE (reduced aromatic aldehyde reduction), a form of the bacteria genetically engineered to be benign.
After refining their process, Sadler and Wallace were able to produce an end product that was 79 percent vanillin and safe for human consumption.
‘This work substantiates the philosophy that post-consumer plastic may be viewed not as a waste product, but rather as a carbon resource and feedstock to produce high value and industrially relevant materials and small molecules,’ they said.
The process could help reduce plastic pollution and meet soaring demand for vanillin, expected to surpass 65,000 tons by 2025
The enzymes used were from E. coli MG1655 RARE (reduced aromatic aldehyde reduction), a form of the bacteria genetically engineered to be benign
Their research is particularly useful given the soaring demand for vanillin, expected to surpass 65,000 tons within the next few years, according to the study, at a cost of approximately $734 million.
In addition to food, vanillin is widely used in cosmetics, candles, pharmaceuticals, herbicides, cleaning products and even garbage bags.
Global demand for vanillin exceeded 40,000 tons in 2018 alone, according to data from Grand View Research.
Vanillin can be distilled from vanilla beans or, more commonly, synthesized from fossil fuels. In addition to food, its widely used in cosmetics, candles, pharmaceuticals, herbicides, cleaning products and even garbage bags
This is believed to be the first demonstration of biological PET upcycling, but if transforming plastics into dessert flavoring isn’t to your taste, scientists have discovered that microbes in cows’ stomachs can actually break down PETs.
Researchers at Austria’s University of Natural Resources and Life Sciences found that the diverse community of microbes in a cow’s rumen — the first and largest of the four compartments that make up the bovine stomach— can decompose plastic faster than single organisms tested in previous studies.
‘A huge microbial community lives in the rumen reticulum and is responsible for the digestion of food in the animals,’ said biotechnology engineer Doris Ribitsch, lead author of a new study in the journal Frontiers in Bioengineering and Biotechnology.
‘So we suspected that some biological activities could also be used for polyester hydrolysis,’ she added, referring to a type of reaction that decomposes plastic.
Millions of tons of microplastics have already found their way into the world’s oceans and waterways. To date, no one has biologically upcycled PET, one of the most common microplastics
The microbes were successful in breaking down PET, as well as two other kinds of plastics— polybutylene adipate terephthalate (PBAT) — a biodegradable material used to make compostable plastic bags — and polyethylene furanoate (PEF), which is derived from renewable, plant-based sugars.
What’s more, Westerner’s cravings for beef means there’s plenty of access to rumen in slaughterhouses so ‘upscaling would be easy to imagine,’ Ribitsch said.
Scientists have increasingly raised the alarm bell on PET and other microplastics, which don’t break down for thousands of years.
Research has shown humans inhale microplastics in our homes and it’s estimated millions of tons of them have already found their way into the world’s oceans and waterways.
A 2016 report warned that, within the next 30 years, all the plastic in the world’s oceans would outweigh fish if current trends continue.
WHAT ARE MICROPLASTICS AND HOW DO THEY GET INTO OUR WATERWAYS?
Microplastics are plastic particles measuring less than five millimetres (0.2 inches).
They have hit the headlines over recent years, as improper disposal has resulted in tonnes of waste making its way into the ocean.
Each year, tonnes of plastic waste fails to get recycled and dealt with correctly, which can mean they end up in marine ecosystems.
Although it’s unclear exactly how they end up in the water, microplastics may enter through simple everyday wear and tear of clothing and carpets.
Tumble dryers may also be a source, particularly if they have a vent to the open air.
Plastics don’t break down for thousands of years and it is estimated that there are already millions of items of plastic waste in the oceans. This number is expected to rise.
Studies have also revealed 700,000 plastic fibres could be released into the atmosphere with every washing machine cycle.
Current water systems are unable to effectively filter out all microplastic contamination, due to the varying size of particles.
The amount of plastic rubbish in the world’s oceans will outweigh fish by 2050 unless the world takes drastic action to further recycle, a report released in 2016 revealed.
More than 80 per cent of the world’s tap water is contaminated with plastic, research published in September 2017 revealed.
The US has the highest contamination rate at 93 per cent, followed by Lebanon and India, experts from the University of Minnesota found.
France, Germany and the UK have the lowest levels, however, they still come in at 72 per cent.
Overall, 83 per cent of water samples from dozens of nations around the world contain microplastics.
Scientists warn microplastics are so small they could penetrate organs.
Bottled water may not be a safer alternative, as scientists have found contaminated samples.
Creatures of all shapes and sizes have been found to have consumed the plastics, whether directly or indirectly.
Previous research has also revealed microplastics absorb toxic chemicals, which are then released in the gut of animals.
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