The best way to provide light at night is store energy and it use it later just like batteries in a flashlight. Researchers have recently discovered that bacteria can create their own version of a battery by rearranging microscopic magnetic particles. In their experiment researchers showed that a group of bacteria removed electrons from minerals during the day. Then at night, bacteria put electrons back into the minerals essentially recharging the minerals and replacing the electrons that had been lost. The bacteria could do this repeatedly. This means that bacteria can store the charge, by holding onto the electrons, and send the charge along to power something external, like a battery could for a lightbulb.
http://www.eurekalert.org/pub_releases/2015-03/eaog-nss032415.php Press release
http://www.sciencedaily.com/releases/2015/03/150326151654.htm News story
http://www.kurzweilai.net/how-bacteria-can-use-magnetic-particles-to-create-a-natural-battery News story
http://www.sciencemag.org/content/347/6229/1473 Original article