Designers turn to the radiance of nature for eco-friendly lighting solutions
December may be the darkest month in the northern hemisphere, but Christmas is undeniably the season of light.
Every December, Americans spend around $645 million kilowatt hours of electricity to brighten their homes. Uswitch research found that the British collectively paid an extra £79 million in energy bills in 2020 on outdoor display lights – an eye watering sum back then and even more so now at a time of energy inflation.
This massive consumer spending on powering Christmas lights tracks a much bigger problem: these decorative trinkets are a major source of pollution. Although LED lights are between 25-80% more energy efficient than traditional incandescent lights, their carbon footprint still has another more stubborn source: the embodied carbon locked up in its materials.
Christmas lights are stuffed with environmentally damaging materials. Fairy lights and outdoor displays almost always come in a plastic casing while their wiring consists of mined metals. Given the globally low rates of plastic and e-waste recycling, most of this will eventually get landfilled.
Data on Christmas pollution overwhelmingly focuses on the energy used to operate decorative lighting while ignoring their embodied carbon. Luma, a sustainable design consultancy, is trying to correct this blindspot by studying the whole life-cycle environmental impact of lighting, from manufacturing to disposal.
The agency notes that the energy costs associated with lighting materials are much harder to cut back than the energy used for operating them. This is because, so far, there are no bio-based substitutes for LED sources nor for metallic components that go into electrical wiring.
How we can reduce the embodied carbon inside lighting fixtures is still an open question, whether in or out of the holiday season. But what if we could add ambience to the holiday home with a biological glow? This is the startling possibility raised by researchers and designers in bioluminescent technology, an emerging niche within the bioeconomy.
Bio-Inspired Glowing Textiles
Sweta Iyer, a designer and scientist, became the first person to demonstrate the feasibility of bioluminescent textiles in her 2020 doctoral thesis at the University of Borås.
She managed to recreate the biochemical mechanisms found in some luminescent fungi, bacteria, stenophores, molluscs, and fish and apply them to common materials.
“The important research question was to understand the bioluminescent reaction mechanism that exists in different living organisms and the selection of the reaction system”, she explained.
In the animal kingdom, the ability to light up one’s body is useful for camouflage, defence, courtship, or attracting prey.
For humans, bio-based lighting holds entirely different values. Bioluminescent textiles sidesteps the problem of having to find bio-based substitutes for carbon-intensive metal writing. Instead, they rely entirely on the light-emitting properties of biochemical reactions.
These lighting technologies come with far fewer embodied emissions and are biodegradable. Applied to common textiles, bioluminscent chemicals eliminates the need for plastic insulation while opening new vistas in sustainable homeware design.
The science behind Iyer’s bioluminescent textiles revolves around two enzymes. These react together, creating light as a byproduct. The chemicals she selected were bacterial luciferase and FMN oxidoreductase, a biobased substrate flavin mononucleotide.
These enzymes are behind a natural bioluminescence system found inside bacteria that inhabit the light organs of ocean animals like squid. Both enzymes used in her experiments were extracted from a marine bacteria species Vibrio photobacterium fischeri.
When oxygen and chemical aldehyde is present, the bacterial luciferase catalyses the oxidation of reduced flavin mononucleotide FMNH2. In the presence of long-chain aldehyde, the FMNH2 then forms FMN-peroxyhemiacetal. This chemical turns into FMN hydroxide. As it returns to its stable, simpler form, called FMN, the compound emits light as a byproduct.
One appealing feature of this chemical reaction is that it is cyclical, extending its life and energy efficiency. If the chemical NADH is present in the mix, the FMN produced by the initial reaction will reduce to FMNH2. This triggers yet another light-emitting reaction to start all over again.
Iyer applied her enzyme system to cellulosic, cotton, polyester, silk, and wool using various techniques: diffusion, screen printing, and digital inkjet printing. She even experimented with glowing patterns on textile surfaces, demonstrating the aesthetic potential of her work. Her chemical cocktail achieves a relative light intensity of 60, 0000, which is equivalent to that of LED light.
Life-saving Glowsticks
Homeware is not the only application for bioluminescence. Sectors as diverse as oil and gas, the military, fisheries, and the events sector are now demanding bio-based solutions to a very different lighting problem: the industrial glowstick.
Glowsticks are a reliable fixture at concerts and parties but they also hold more serious applications. These non-flammable, portable lights are used in confined space rescue, mine safety and evacuation procedures. Offering illumination without electricity, they reduce the risk of explosion in spaces where there may be a gas leak.
As useful as they are, the problem with conventional glowsticks is that their fluorescent liquids are based on petrochemicals. These are extremely hard to dispose of safely. Billions of these devices are discarded every year to leach into the environment – a particularly serious problem within the fishing industry, where glowsticks are sometimes dangled underwater as prey lures for fish.
Nyoka is a Canadian company that produces bioluminescent and biodegradable versions of these toxic industrial tools. Their glowsticks are based entirely on patented biochemical reactions that generate more photons per gram of reactive substance than conventional chemical glowsticks.
The superior lighting performance of bio-glowsticks compared to their petrochemical counterparts indicates how promising the field of bioluminescent tech is. When bio-based versions out-perform conventional materials on essential functions, it makes scaling and adoption far more likely.
Iyer’s bioluminescent textiles and Nyoka’s bio-based glowsticks both involve isolating the core enzymes that dirve biological light-production in certain organisms. Yet some researchers in the bioluminescence space are trying to harness the glowing power of living creatures themselves, not just their underlying chemistry.
The Soft Glow Of Bacteria
A French biotech start-up named Glowee has pioneered what it calls “biological lamps”: clear vessels full of nutrient and oxygen liquid that sustain living, light-producing marine bacteria. Evoking their ocean origins, they give off a soft turquoise glow.
Glowee’s lighting solutions aim to foster ecologically beneficial relationships between human and non-human species. Their biological lamps, which were trialled this year on the streets of a French hamlet called Rambouillet, are designed to cut down on the light and visual pollution associated with electric versions.
Glowee’s living lamps are stocked with a bacterium called Aliivibrio fischeri whose natural metabolism comes equipped with a light-emitting biochemical system. Switching off the lamps is easy: cutting off the air flow in the vessels places the bacteria into a dormant state.
The bacterium-feeding liquid in the vessels is biodegradable and the company claims making it uses less water and carbon dioxide than manufacturing LED lights.
Since 2016, Glowee’s has worked to lengthen the lifespan of their bacterial lighthouses. Seven years ago, their living lamps would die down after about three hours, limiting their applications to parties and events. By 2019, Glowee has pushed the lighting hours up seven days. Now, the maximum is one month.
Before Glowee’s biological lamps go mainstream, the startup must improve the light intensity of their bacteria. Currently, they are less luminous than the average electrical light.
Nonetheless, Glowee is gaining serious backers who are betting on future improvements to the technology. France’s state-run electricity grid company ERDF has pumped €1.7m into the company while France’s National Institute of Health and Medical Research had provided it with technical support.
With bioelectronic replacements for metal circuitry still a long way off, lighting is still one of the big challenges of sustainable design. Bioluminescent organisms show us that it is not unsurmountable, supplying us with simpler ways to reduce the environmental impacts of light fixtures both inside and outside the home.
