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Microbes to the Rescue?

Plastics go into consumer products from baby rattles to yachts, and over 300 million tons are manufactured worldwide each year. Their durability (water does not dissolve plastics) is useful, but plastics’resistance to deterioration turns bad at disposal time. Discarded plastics of all colors and shapes litter the Earth; the oceans have millions of square miles of floating plastics (Great Pacific Ocean Garbage Patch), killing marine life and causing other damage.

Most of man’s traditional garbage – paper,food and so on – is broken down over time in landfills, in fresh or salt water or otherwise by a diverse army of microbes. Dead trees, animal waste and dead fish all rot in time, and their carbon molecules become available for new uses. Plastics are different. They are polymers, long strings of carbon molecules which man, in the past century, has figured out how to glue together.

Mother Nature has not had enough time to design microorganisms to break down the new carbon chains, but that may change quickly.

In 2016 Japanese scientists discovered, in a garbage dump, a bacterium which had evolved to eat the common PET plastic used to make plastic bottles. The bacterium produced an enzyme which broke the bonds connecting PET’s molecular building blocks. The smaller chunks were bite-sized for bacteria, which used the carbon for energy much as humans burn carbon and exhale carbon dioxide. Scientists then genetically engineered the bacterium to make it more efficient in breaking down PET.

Mother Nature is good at solving microbe-level problems. Recall that many antibiotics created to defeat harmful bacteria are themselves defeated as the bacteria mutate and develop immunities to doctors’ best drugs. Plastic-killers will probably evolve, with or without help from our research, to feed off all the juicy hydrocarbon chains man has produced, but when and with what byproduct chemicals released into the environment?

The fictional Dr. Frankstein warns of the unintended, unexpected consequences that high-tech manipulation of nature sometimes has. Bottom line, it would be wise for man to limit production of plastics and to recycle as much as possible.

 

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