Optimization of rhamnolipid production by biodegrading bacterial isolates using Plackett-Burman design.

Biosurfactants are biological surfactants produced by microorganisms. Pseudomonas species are well known for the production of the rhamnolipid biosurfactant. In this work, the production of rhamnolipid biosurfactant by Pseudomonas spp. was investigated and further optimized. Two Plackett-Burman designs to study the effect of carbon source, nitrogen source, C/N ratio, iron concentration, magnesium concentration, phenol toxicity, pH, temperature, agitation and sampling time were tested. The first design revealed an optimization that increased biosurfactant productivity by almost two to fivefolds for the tested isolates. However, using the second design showed no remarkable increase in biosurfactant productivity. An additional validation run was adopted using the predicted optimal medium with predicted optimal conditions. The validation run showed remarkable increase in the productivity of the tested isolates. The use of microorganisms with biodegradation ability coupled with optimization of the parameters affecting productivity provides an efficient strategy for biosurfactant production.