生物表面活性剂产生菌的筛选及其发酵条件的初步优化

Screening and Primary Optimizing of Cultural Medium of Biosurfactant Producing Strain

以石油为C源,经过富集培养从石油污染土壤中筛选出15株具有较强产生物表面活性剂能力的菌株。其中菌株BS-5产生物表面活性剂的能力最强,该菌发酵液的表面张力可达27.3 mN/m(空白发酵液表面张力为54.5 mN/m)。通过红外光谱分析发现该菌产生的生物表面活性剂为糖脂类物质。另外,通过正交试验对该菌的培养基条件进行初步优化,结果以植物油10g/L、MgSO_4 0.2g/L、K_2HPO_4 1.0g/L、KH_2PO_4 1.0g/L、蛋白胨1.0 g/L、FeSO_40.05g/L、CaCl_2 0.02g/L、初始pH值7.5为最佳。通过16S rDNA测序结果表明该菌为铜绿假单胞菌(Pseudomonas aeruginosa)。

Biosurfactant producing strains were screened through enrichment from the oil sludge with crude oil as sole carbon source and 15 strains which could produce higher yield of biosurfactant were obtained. Strain BS-5 could produce highest biosurfactant and be able to reduce the surface tension of fermentation broth to 27.3 mN/m （the surface tension of pure water is 71.5 mN/m）. Analytic results by FT-IR showed that the biosurfactant of the strain was a kind of glyeolipid. In addition, the cultural conditions of the strain were primarily optimized by using orthogonal experiment method. The best result was： vegetable oil 10 g/L, MgSO4 0.2 g/L, K2HPO4 1.0 g/L, KH2PO4 1.0 g/L, peptone 1.0 g/L, FeSO4 0.05 g/L, CaCl2 0.02 g/L and initial pH 7.5. The strain was identified as Pseudomonas aeruginosa according to microscope observation and the 16S rDNA gene sequence.