Tuesday, March 17, 2009

Measurement of Biosurfactant Activity

Biosurfactant activity was measured by an oil displacement test. This method is so sensitive that only a small amount of sample is required to measure the surfactant activity. Here is the method:

  1. A sample is solubilized or suspended in 10 micro liters of 10% acetonitrile or 0.1 M Tris-Cl (pH 8) buffer.
  2. After solubilized or suspended , a sample was put on the center of an oil membrane which was formed on the surface of water in a large size petri dish (15 cm diameter).
  3. The size of the resultant oil-displaced circle area reflects the activity of a surfactant.
  4. The larger the size is, the higher the activity of a surfactant is.
  5. One BS unit was defined as the amount of surfactants forming 1 cm square of oil displaced area.
  6. The surface tensions were measured using a ring tensiometer (K6; Kruss, Germany).


Reference: Number 3 on References