Enhanced production of biosurfactant by a marine bacterium on statistical screening of nutritional parameters

Marine microorganisms can serve as rich sources for novel biosurfactants with diverse biological activities. In the present investigation, the nutritional requirement for the growth and biosurfactant production by a marine bacterium was determined using a Plackett–Burman-based statistical screening procedure. Six out of the eleven factors of a reported production medium were found to be critically affecting the biosurfactant metabolism. Glucose, the carbon substrate of the medium was the most influential factor with an effect contribution of 78.13% and a very low p-value of <0.001. Glucose, NH4NO3 and FeSO4·7H2O had a direct proportional correlation with biosurfactant production while, K2HPO4, KH2PO4 and MgSO4·7H2O showed inversely proportional relationship with biosurfactant production in the selected experimental range. A simpler modified medium (MM) was formulated based on the statistical screening results. Modified medium combination (MM-1) having the following composition in g l−1: glucose 30; NH4NO3 6.0; K2HPO4 1.1; MgSO4·7H2O 0.3; KH2PO4 2.8 × 10−2 and FeSO4. 7H2O 6 × 10−2 showed 84.7% increase in biosurfactant yield over the reported medium (SM). Fourier transform infrared spectroscopy and thin layer chromatography studies showed that the biosurfactants produced in the modified medium (MM) were similar to those produced in the reported medium (SM).