Luciferase

Luciferase refers to enzymes producing bioluminesence.

Scientists use bioluminescence in many interesting applications:

• Whole-animal imaging
• ATP sensing
• Added to an organism’s genome

There’s an interesting claim that the biological process is 80-90% efficient, which is much more efficient than LEDs. The chemical equation for bacterial liciferase (accoring to Wikipedia) is here:

$$FMNH_2 + O_2 + RCHO \to FMN + RCOOH + H_2O + light$$