A student may have found a solution to one of theworld's most urgent environmental crises – breeding bacteria capable of “eating” plastic and potentially breaking it down into harmless by-products.
The microbes degrade polyethylene terephthalate– one of the world's most common plastics, used in clothing, drinks bottles and food packaging.
It takes centuries to break down, in the meantime doing untold damage to its surroundings.
Morgan Vague, who is studying biology at Reed College in Oregon, said the process, if sped up, could play a “big part” of solutions to the planet's plastic problem, which sees millions of tonnesdumped in landfill and oceans every year.
Around 300 million tonnes of plastic is discarded each year, and only about 10 per cent of it is recycled.
“When I started learning about the statistics about all the plastic waste we have, essentially that told me we have a really serious problem here and we need some way to address it,” Ms Vague told .
After she began learning about bacterial metabolism and “all the crazy things bacteria can do”, the student decided to find out if there were microbes out there able to degrade plastic.
She began hunting for microbes adapted to degrade plastic in the soil and water around refineries in her hometown of Houston.
Taking her samples back to college in Portland, Oregon, Ms Vague began testing around 300 strains of bacteria for lipase, a fat-digesting enzyme potentially capable of breaking down plastic and making it palatable for the bacteria.
She identified 20 that produced lipase, and of those three that boasted high levels of the enzyme.
Next she put the three microbes, on a forced diet of PET she cut from strips of water bottles.
She was stunned to find the bacteria worked to digest the PET.
“It looks like it breaks it down into harmless by-products that don't do any environmental damage, so right now what it's doing is breaking down the hydrocarbons within the plastic, and then the bacteria is able to use that as food and fuel,” she said.
But she warned there was a “long way to go” until we will start to see the microbes eating plastic at anything like the rate useful in disposing of plastics.
The next step, said Jay Mellies, a microbiologist who supervised MsVague's thesis, is to speed it up, improve pre-treatments on the PET to make it more palatable, and to get the bacteria to work on a variety of plastics.
“The plastic problem is huge and all of us are beginning to be aware of it,” he said. “This is not going to be the total solution, but I think it's going to be part of the solution.”
Professor John McGeehan, a biologist at the University of Plymouth, who has done research into plastic-degrading enzymes, warned MsVague's research was in its early stages and more testing was needed.
“These are naturally occurring bacteria that are out there in the environment and we're not looking to genetically engineer them, we're just trying to isolate bacteria and then treat the plastic in a way the bacteria can naturally digest it.”