Surfactin is a kind of lipopetide surfactant with capacity of reducing interfacial tension, which makes it to be great potential in various applications of biotechnology and environmental protection. At present, the lower yield, higher cost of the separation and purification hinder the application of biosurfactin. Therefore, it is especially necessary to improve the yield of biosurfactin by breeding high product strain, optimizing the fermentation conditions and purification technology. The effects of carbon sources, nitrogen sources, phosphate, metal ions, amino acids, and pH value on the production of biosurfactin by Bacillus pumilus BA06 was studied. Further the orthogonal experiment was used to optimize the four main factors of yeast powder, peptone, maltose and Na2HPO4 which were shown to influence the production of surfactin greater in the single factor experiment. The optimal fermentation medium was obtained by the single factor experiment and orthogonal experiment as following: malt sugar 2.97%, NaNO3 0.30%, yeast extract 0.81%, peptone 1.10%, MgSO4 0.01%, CaCl2 0.01%, KH2PO4 0.24%, Na2HPO4 4.47% and pH 7.0. Based on the optimized conditions, 0.5 L fermentation was performed to achieve 6.48g/L raw biosurfactin with 3.53-fold increase more than the original production (1.43 g/L). B. pumilus BA06 is shown to be able to product the biosurfactin, which can be increased significantly by optimizing the fermentation conditions and medium components. These results indicated that this bacterial strain is of great potential in production of biosurfactin.
