Lights powered by living organisms

Glowee, a French startup, has transformed the small town in France into the subject of an odd lighting experiment.

A number of bioluminescent cylindrical tubes emitting an azure, ethereal glow are already illuminating the waiting room of the town's COVID-19 vaccination center. These otherworldly lights are powered by living organisms through a process known as bioluminescence.

This phenomenon, where chemical reactions inside an organism's body produce light, can be observed in many places in nature. Organisms as diverse as fireflies, fungi and fish have the ability to glow through bioluminescence. It is present in 76% of deep-sea creatures and has independently evolved dozens of times, including at least 27 occasions in marine fish alone.

The uses of bioluminescence in the natural world are just as wide-ranging. Fireflies light up to attract mates while some species of algae glow when the surrounding water is disturbed. Deepsea anglerfish allow bioluminescent bacteria to take up residence on a lobe above their head as a tantalising lure for prey.

Glowee, employs a marine bacterium called Aliivibrio fischeri collected off the coast of France to light up rooms and, potentially, whole cities in the future.

"Our goal is to change the way in which cities use light," Sandra Rey, founder of Glowee, told BBC. "We want to create an ambiance that better respects citizens, the environment and biodiversity – and to impose this new philosophy of light as a real alternative."

The startup keeps the bacteria inside saltwater-filled tubes. This allows bacteria to circulate in what is essentially a luminous aquarium, where a combination of basic nutrients is given readily and the air is pumped through the water to provide oxygen.

The light is produced by internal biochemical processes that are part of the organism's normal metabolism, which is why running it requires essentially no energy other than that required to manufacture the food the bacteria ingest. When they want to switch off the lights, they shut off the air supply, which puts the bacteria in an anaerobic state, where they no longer create bioluminescence.

Harnessing bioluminescence to light our cities?

The startup believes that bioluminescence produced by bacteria could be an energy-efficient, sustainable solution to easing our dependency on electricity for lighting, which is largely produced by burning fossil fuels.

The entire process is dependent on living organisms, which is why it faces several hurdles that need to be overcome before it can be employed on a large scale. One shortcoming is that the process creates a fraction of the light. The startup is improving bacteria without using genetic modifications, making them more efficient in terms of light production. They could also be sensitive to temperatures, so Glowee is working on these issues to light the way for more towns and cities to follow suit.

Source: https://interestingengineering.com/french-town-bioluminescent-organisms