短小芽孢杆菌BA06产表面活性素培养基组分的优化

本研究发现短小芽孢杆菌(Bacillus pumilus)BA06菌株具有发酵产生表面活性素的能力,并对发酵培养基的组分进行了优化.单因素试验发现,麦芽糖、酵母粉、蛋白胨、磷酸氢二钠对其产量影响较大;对上述4个因素进行正交优化组合得到该菌产生表面活性素的最适培养基:麦芽糖2.97%、NaNO_30.30%、酵母粉0.81%、蛋白胨1.10%、MgSO_40.01%、CaCl_20.01%、KH_2PO_40.24%、Na_2HPO_4 4.47%,pH 7.0;在此条件下进行了0.5L的发酵实验,表面活性素粗品产量从原来的1.43g/L增加至6.48g/L,提高了3.53倍.结果表明短小芽孢杆菌BA06菌株具有进一步开发、生产表面活性素的潜力.

Optimization of fermentation conditions of surfactin by Bacillus pumilus BA06

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.