Superbugs shaping-up to take-on ocean plastics

As reported by Nautilus, findings published in the journal Global Home of Chemical Engineers suggests scientifically-engineered superbugs could soon help rid our oceans of plastic debris. 

With saltwater organisms and bacteria unable to break down plastics, reversing the build-up of plastic waste in our oceans remains a real challenge. As a result, phenomena such as the Great Pacific Garbage Patch continue to grow. 

In recent years, scientists have identified several land-based bacteria that can consume certain types of plastic – including polyethylene terephthalate, or PET, a form of polyester widely used in bottles, cans, food packaging, and clothing. 

One such bacteria, called Ideonella sakaiensis, produces a specific enzyme that breaks the long PET molecules into smaller, simpler compounds. Essentially, the bacteria releases this enzyme into its surroundings, the enzymes break down the plastic, and the bacteria consumes the leftovers. The downside though, is that these bacteria don’t do well in marine environments. 

Thankfully, Nathan Crook of North Carolina State University, and Tianyu Li, a Ph.D. candidate in Crook’s lab, think they’ve found a fix. 

The team extracted the genes for PET-breaking enzymes from the land-dwelling I. sakaiensis and inserted them into another bacteria, Vibrio natriegens. This new bacteria thrives in saltwater and multiplies quickly – two characteristics which could make it efficient at consuming large quantities of ocean plastics.

Crook and Li transferred the relevant genes into V. natriegens on a tiny snippet of genetic code known as a plasmid. Once floating inside the bacterial cell, the plasmid is able to instruct V. natriegens to make the necessary plastic-pulverising enzyme.

Unfortunately, the scientists haven’t yet managed to incorporate the enzyme-coding genes into V. natriegens’ genome. Therefore, when the bacteria multiply, all new generations lack the essential plastic-degrading ability. What’s more, while I. sakaiensis is able to consume the molecules left over once the enzyme has done its work, the genetically modified V. natriegens currently cannot. But, with a few more tweaks, Crook believes this modified bacteria could work as well in the ocean as others do on land. 

Of course, even once this process is perfected, sprinkling genetically-modified bacteria into the ocean would be risky for the ecosystem. As a result, Crook and his team envisions the ocean clean-up operations using a fleet of large boats to suck the plastic debris into their hulls before ‘feeding’ it to bacteria housed inside hermetically sealed reactors.