Fig. 2
A serrawettin-type biosurfactant from ZS6 is found at high-level when cultivated in olive oil medium. a CMC analysis of crude extract derived from supernatant of ZS6 culture. X- and Y-axes indicate concentrations of biosurfactant crude extract (g L−1) and surface tension ST (mN m−1). b Thin-layer chromatographic analysis of the biosurfactant crude extract. Lanes 1, 2, and 3 show extract of iodine vapor staining, ninhydrin staining prior to (bef) and after (aft) acid hydrolysis (AH), respectively. c High capability of methylbenzene emulsification. Images show 24 h after mixing the supernatant of ZS6 culture (super), blank medium, and olive oil with methylbenzene (6:1 v/v). d Image shows the result of agar gel immunodiffusion assay. ZS6 biosurfactant is a nonionic cyclolipopeptide. SDS and CTAB are anionic and cationic surfactants, respectively. e Growth curve analysis of ZS6 under various growth conditions indicated. f Biosurfactant production from ZS6 under various growth conditions. g Efficiency of biosurfactant production per unit of cell mass under various growth conditions. The ratio between level of cyclic lipopeptide (cLP) or OSZ and CDW is based on measurements at 36 h after growth. YE for yeast extract, OO for olive oil, SO for sunflower oil, CO for coconut oil, and HD for hexadecane. h Productivity of biosurfactant in ZS6 under various growth conditions. The display is identical to g