Driving past the Vangarde John Lewis on a Sunday night, it is striking to see the sheer number of unnecessary lights left on to illuminate the car park and surrounding shop windows.
Aside from light pollution problems, the cost of running these lights 24 hours a day must be extortionate. Never mind the fossil fuel consumption and carbon emission to power them.
With solar panels becoming as common as roof tiles, you would think there would be a more sustainable way to keep these centres illuminated at night.
Well now there could be. A French company aptly named ‘Glowee’ is trialling bioluminescent bacteria to light up the streets. The Aliivibrio fischeri bacteria are usually found camouflaging the Hawaiian bobtail squid by counter-illumination.
The bacteria occupy the squid’s light organ and produce the same amount of light on the bottom of the squid as that hitting the top so it is effectively invisible from above.
The bacteria has been isolated and colonised in gels with the optimum amount of nutrients to keep them alive. Culturing bacteria can be very difficult so the fact that the bacteria can be grown in vitro is a breakthrough in itself. They can then bioluminesce for up to three days generating a calm blue-green glow to light up shop windows. This by-passes the French law which does not allow lights in shop windows between the hours of 1am and 7am. A similar law in the UK would help reduce consumption.
Bioluminescence is simply the production of light from a chemical reaction in an organism. It differs from other forms of luminescence such as fluorescence and phosphorescence which require light energy to initiate them rather than a chemical reaction. For every bioluminescent reaction, two general chemicals are needed: a luciferin (the molecule that produces the light) and a luciferase. Luciferase is the enzyme required to catalyse the reaction. The luciferase catalyses the oxidation of luciferin, producing an inactive oxyluciferin and light. Another mechanism for bioluminescence is the production of a photoprotein from the luciferin. In this process, luciferase and cofactor oxygen bind together. Upon adding an ion, usually calcium, the photoprotein is activated to produce light.
Following the successful three day experiment with bioluminescent bacteria, now the challenge is to prolong the luminescence for months, making this a viable lighting option.
To do this, Glowee are investigating the optimal nutrient concentration and mechanisms to remove waste from the bacteria, providing living conditions for long periods of time. Research into the practicality of integrating these systems while keeping the mechanics aesthetically pleasing and discrete is necessary.