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Genetically Modified Plants To Produce Natural Lighting
kkleiner writes "A team has launched a crowdsourcing campaign to develop sustainable natural lighting by using a genetically modified version of the flowering plant Arabidopsis. Using the luciferase gene, the enzyme responsible for making fireflies glow, the researchers will design, print, and transform the genes into the target plant. The project, which was recently launched on Kickstarter, has already raised over $100k with over a month left to go."
Just kidding. Here's the Kickstarter Link.
This was my first concern. Some back-of-the-envelope calculations:
Photosynthesis is pretty lousy in terms of thermodynamic efficiency. About 1% of the light that hits a plant is converted to useful chemical energy. The plant will have to use most of that energy for its metabolic processes. Luciferase itself is a very efficient enzyme, however, so I'll generously assume that 10% of the energy that the plant captures can be turned into useful light. So the overall efficiency can't be much higher than 0.1%. By comparison, solar cells are around 10% efficient, and LEDs 20%, so at first glance the luciferase plant seems to be an order of magnitude less efficient than the solar powered flashlight my in-laws gave me for christmas.
In absolute terms, there is about 100 watts/meter^2 of energy in sunlight. If you've got a one-square-meter window full of the hypothetical plants sitting in sunshine all day, let's say they can absorb 1500 watt-hours, and then convert 1.5 watt-hours into useful light. That'd be comparable to running a 5-watt LED for an hourish, which could be useful if you could turn the luminescence on and off at will. But if the plant is glowing all night and only a portion of the light is emitted in a useful direction, maybe the window-full-of-plants would give off light comparable to the little cluster of LEDs on the front of my computer. So overall I'd say that the idea is not completely impossible, but still totally impractical.
Adding the Luciferase gene is fine and dandy. But to get the plant to glow, it also has to produce the appropriate luciferin. The photo they use of a glowing tobacco plant was produced by watering the tobacco with luciferin solution and then using a very long exposure. (http://en.wikipedia.org/wiki/File:Glowing_tobacco_plant.jpg)
That said, the luciferin found in dinoflagelates is derived from chlorophyll (http://en.wikipedia.org/wiki/Luciferin) and it is conceptually possible to introduce the relevant algae genes into their plant... once the genes have been identified. This sort of metabolic engineering is a MUCH bigger task than the Kickstarter campaign people are planning for.
The energetic difficulty could be worked around by making the plant into a biological capacitor... where it builds up luciferin all day and then discharges in a flash at night. The plants wouldn't be of any use in landscape lightly, but they would be a really cool landscape feature. The downside is they might drive any local fireflies insane.