title: Pseudomonas aeruginosa biosurfactant production in continuous culture with glucose as carbon source.
abstract: Rsan-ver, a strain of Pseudomonas aeruginosa isolated at this department, was used for the development of a continuous process for biosurfactant production. The active compounds were identified as rhamnolipids. A final medium for production was designed in continuous culture by means of medium shifts, since the formation of surface-active compounds was decisively influenced by the composition and concentration of the medium components. In the presence of yeast extract, biosurfactant production was poor. For the nitrogen-source nitrate, which was superior to ammonium, an optimum carbon-to-nitrogen ratio of ca. 18 existed. The iron concentration needed to be minimized to 27.5 micrograms of FeSO4 X 7H2O per g of glucose. A carbon-to-phosphate ratio below 16 yielded the maximum production of rhamnolipids. The final productivity dilution rate diagram indicated that biosurfactant production was correlated to low growth rates (dilution rate below 0.15 h-1). With a medium containing 18.2 g of glucose liter-1, a biosurfactant concentration (expressed as rhamnolipids) of up to 1.5 g liter-1 was obtained in the cell-free culture liquid.
mesh_terms: D000645:Ammonium Sulfate / Q000378:metabolism; D003470:Culture Media; D005947:Glucose / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000254:growth & development*; D013501:Surface-Active Agents / Q000302:isolation & purification*
chemical_list: D003470:Culture Media; D009566:Nitrates; D013501:Surface-Active Agents; C031618:sodium nitrate; D005947:Glucose; D000645:Ammonium Sulfate