A Biosurfactant-Producing Pseudomonas aeruginosa Strain

A Pseudomonas aeruginosa strain producing an extracellular surfactant (biosurfactant) was isolated. The growth of this strain, referred to as 50.3, on a mineral glycerol-containing medium produces an emulsifying activity (60%) and decreases the surface tension of the culture liquid by a factor of 2.8 (to 25 mN/m). The optimum conditions for its growth and production of biosurfactants are intense aeration, pH 7.0–8.0, and the presence of Mg²⁺. The optimum biosurfactant properties were achieved when glucose was used as the only source of carbon and energy and NH₄Cl was used as a source of nitrogen. The biosurfactant was isolated from the culture liquid by extraction and precipitation.