This year’s Cambridge iGEM team has made a tiny, wireless lightbulb filled with bioluminescent bacteria! There are two main ways of engineering luminescence in E. coli (I assume these are E. coli, correct me if I’m wrong!). One is to express the luciferase gene from fireflies, which adds ATP and oxygen to the chemical luciferin, producing oxyluciferin and yellow, green, or red light.
Since the lightbulb is blue, this bacteria is probably expressing the Lux operon from Vibrio fischeri, which use their bioluminescence in an awesome underwater symbiosis. From the Cambridge iGEM wiki:
Some strains use their ability to emit light to form symbiotic relationships. A number of deep sea fish and squids have specialised light organs which harbour populations of bacteria which help their hosts by emitting light. One such example is the partnership between the Bobtail squid and the bacterium Vibrio fischeri. At night squid hunt high in the water column, attacking from above. But on moonlit nights the prey can evade capture by sensing their shadow. The bobtail squid overcomes this by emitting light using V. fischeri, replacing the moonlight it blocks. This allows is to hunt by stealth.
The cluster of genes that causes the bioluminescence is made up of five genes, luxA and luxB make the luciferase enzyme, and luxC, luxD, and luxE produce tetradecanal, the chemical substrate that the luciferase acts on, like luciferin in fireflies. Five genes in a cluster can be moved around into other bacteria on an iGEM timescale and budget, but naturally bioluminescent bacteria are actually pretty easy to culture at home using normal kitchen ingredients to isolate the bacteria that are living on squid from the fish market.
The lightbulb is a great demonstration of their ability to engineer bioluminescence and especially interesting given the efficiency of luciferase vs. a real incandescent lightbulb. From wikipedia:
The reaction is very energetically efficient: nearly all of the energy input into the reaction is transformed into light. As a comparison, the incandescent light bulb loses about 90% of its energy to heat.
I’m really looking forward to meeting the team at the Jamboree and seeing more of their cool results!
UPDATE: Also check out Lab Rat’s awesome post with much much more insider info and photos about the bioluminescent bacteria!