Abstract: An efficient biosurfactant-producing strain A3 was isolated from the soil of Liaohe oil field. According to the analysis of 16S rRNA sequence, it was identified as Pseudomonas aeruginosa. The analysis by TLC and infrared spectrum showed that the biosurfactant produced by strain A3 belongs to glycolipid. The characteristics of biosurfactant in the viscosity reduction of heavy oil were investigated. The results showed that the dosage of biosurfactant, temperature and salinity had important effects on viscosity reduction of heavy oil. The small change in viscosity could be observed in the range of 30℃ to 50℃, and viscosity reduction rate of 85.7% could be obtained. The viscosity reduction rate of 77.1% could be obtained under the salinity of 20 g/L. Using 3.33 mg/L biosurfactant, the viscosity reduction rate of 96.7% could be obtained under 30℃ for 30 min. The biosurfactant from strain A3 is superior to chemical surfactant C16H33N(CH3)3Br in dosage, sensitivity and performance in viscosity reduction.

Key words: screening, biosurfactant, surface tension, heavy oil, viscosity reduction