Abstract

Biosurfactant production by Pseudomonas aeruginosa by utilizing diesel as the source of energy and carbon was studied in this research. Biosurfactant-producing strain of the organism was isolated from hydrocarbon-contaminated water and grown in a mineral medium supplemented with diesel. Production of biosurfactant was assayed by monitoring the increase in cell concentration, biosurfactant concentration, emulsification index and decrease in surface tension. Highest level of cell concentration and biosurfactant concentration (3.3^108CFU/ml and 0.0108mg/ml respectively) were obtained at 132hrs. Emulsification index reached its maximum with 33.3% at 108hrs. Surface tension reached its minimum at 120hrs with a value of 1.1^10-6N/m. The results showed that diesel can be utilized by P. aeruginosa to produce biosurfactant and early stationary phase isolates can be used to obtain higher yield. It also revealed the increasing potentiality of microorganisms in the aspect of oil spill cleanup and rapid reclamation of contaminated lands and water bodies.

Key words: Biosurfactant, diesel, surface tension, emulsification index, cell biomass, Pseudomonas aeruginosa.