Detection of Rhamnolipid Production in Pseudomonas aeruginosa

Large variety of microorganisms produce potent surface-active agents, biosurfactants, which vary in their chemical properties and molecular size. Rhamnolipids are naturally occurring glycolipids produced by Pseudomonas aeruginosa species of bacteria. The enormous diversity of biosurfactants makes them an interesting group of materials for application in many areas such as agriculture, public health, food, health care, waste utilization, and environmental pollution control such as in degradation of hydrocarbons present in soil. Their ability to reduce surface tension is a major characteristic of surfactants, which is the key ingredient used in detergents, shampoo, toothpastes. Four strains of Pseudomonas aeruginosa obtained from oil contaminated soil with diesel, kerosene or benzene using four detection methods: Blood hemolysis, Oil spreading technique, cetyl trimethylammonium bromide ( CTAB ) agar plate, and Emulsifying activity. Ten out of eleven strains tested demonstrated rhamnolipid production in one or more of the techniques used and with variable amounts, with Pseudomonas aeruginosa strain D and T displaying positive and high productivity in all methods used. A new modification of oil spread technique was performed in the present study as this method was found to be the most efficient, easiest, and reliable among the others.