Background: Light can be absorbed by bacterial pigment and affects its growth. Prodigiosin is a red
pigment found in various bacterial species. The purpose of this study was to investigate the impacts of
light on prodigiosin production, biomass formation, and membrane integrity of
Serratia marcescens
y2.
Results: S. marcescens y2 grew better and produced more intracellular prodigiosin in darkness than in
illumination. The pigment leakage ratio from cells was detected more in light than in darkness
conditions. Ethidium bromide uptake assay could visually prove the prodigiosin-related loss of
membrane integrity under illumination. A higher concentration of malondialdehyde (MDA) was detected
in light-treated culture than in darkness. Tests of different light treatments (red, yellow, blue and green)
showed that the maximum extracellular pigment and the minimum biomass formation and intracellular
pigment were obtained in green light.
Conclusions: Prodigiosin could absorb light, and then initiate phototoxicity damage of the
cytomembrane.
