Effect of various growth conditions on pigmentation of Serratia marcescens.

Prodigiosin biosynthesis in Serratia marcescens depends on growth conditions. In the presence of various concentrations of NaCl, pigment synthesis started later, but up to 4-5% NaCl increased prodigiosin accumulation per biomass unit. Visible light (< 2,000 lux) influenced pigmentation without changing the growth characteristics of the culture. The maximum prodigiosin content in dark and light cultures was observed on days 3-4 and 2-3, respectively. The influence of illumination conditions on pigmentation of S. marcescens was demonstrated. Light directly affects the pigment itself which is synthesized by the culture. Growing cells contain mono and dimer forms of prodigiosin in glycerol, with light influencing these pigments.