How do bioluminescent bacteria produce light using FMNH2?

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time-lapse photo of fireflies — Bioluminescence Time-lapse image of fireflies in the Catskill Mountains, New York. Firefly light is a cold light, with approximately 100 percent of the energy given off as light and only a minute amount as heat. Only light in the visible spectrum is emitted.

Bioluminescent bacteria produce light through a specific enzymatic process involving the oxidation of reduced flavin mononucleotide (FMNH $_{2}$ ).

In this reaction, the enzyme bacterial luciferase catalyzes the interaction between FMNH $_{2}$ and molecular oxygen. This process forms a long-lived intermediate complex. Subsequently, this complex reacts with a long-chain aliphatic aldehyde molecule, such as decanal, which triggers the emission of light.12