Abstract
Prodigiosin is a red pigment characterizing S. marcescens and produced in abundance by the bacterium on peptone-glycerol (PG) agar plates incubated at 30°C. In a PG liquid culture, however, S. marcescens was unable to produce prodigiosin. On addition of silica gel (8.0 mg/ml) to the liquid medium, S. marcescens became able to proliferate better and produced prodigiosin and serrawettins (biosurfactant) profusely. The effect of the silica gel on the production of exolipids was dependent on source (manufacturers). By microscopic examination, sessile bacterial populations were recognized on the silica particles active in the promotion of prodigiosin production, but not on the particles unable to promote the production. Prodigiosin and serrawettins are structurally unrelated but seem to have the same production control systems responding to temperature (T. Matsuyama, et al., J. Gen. Microbiol., 132, 865-875, 1986) and silica gel.
