Today, the world consumes 120 million tons of the chemical ethylene to make the world’s most widely used plastics. Almost all of that ethylene is derived from fossil fuels. Between 1.5 to 3 tons of carbon dioxide is released for every ton of ethylene produced, which is why plastic has such an enormous carbon footprint. Now, researchers have inserted a gene into bacteria that turns it into one of the world’s most efficient factories for ethylene by eating carbon dioxide, instead of releasing it into the air.
The new cyanobacterium works in the opposite way of traditional plastic production: Its photosynthetic capabilities means it harnesses today’s photons from sunlight (as opposed to old photons stored in the energy of chemical bonds in petroleum) to add carbon from the air to ethylene molecules. This saves six tons of carbon dioxide emissions for every ton of ethylene created: Three tons are absorbed by bacteria and three are avoided from the usual fossil fuels, says the National Renewable Energy Laboratory.
"Our peak productivity is higher than a number of other technologies, including ethanol, butanol, and isoprene," said NREL principal investigator, Jianping Yu, in a release from the Lab. "We overcame problems encountered by past researchers. Our process doesn’t produce toxins such as cyanide and it is more stable than past efforts. And it isn’t going to be a food buffet for other organisms."
The organism—cutely named Synechocystis—churns out about 170 milligrams of ethylene per liter each day, more than the photosynthetic productivity of other algae biofuels such as ethanol or butanol. And unlike other bacterial cultures, the Synechocystis strain also grows in nutrient-rich seawater and continues to yield ethylene gas over long periods (previous attempts only produced ethylene for short periods). Natural plastic might be just around the corner. And how will we get rid of it? Feed it to the mushrooms.