堆肥中生物表面活性剂产生菌的筛选及培养条件优化

Optimization on the Screening and Culture Condition of Biosurfactant-producing Bacteria from Compost

[目的]筛选堆肥中生物表面活性剂产生菌，优化其培养条件。[方法]采用富集培养、菌种纯化等方法从农业好氧堆肥中筛选出能产生生物表面活性剂的菌株，并采用正交试验对菌株的培养条件进行优化。[结果]从农业好氧堆肥中筛选出1株能产生生物表面活性剂的菌株BS-2，该菌株能将发酵液的表面张力降到40mN／m以下，在温度20—100℃和pH值6．0～9．5条件下，其表面张力始终保持在40mN／m以下，具有良好的表面活性及对堆肥环境的稳定性。该菌株的最佳培养条件为：可溶性淀粉25．0g/L、NH4NO3 8．0g／L、KH2PO4 2．0g／L、K2HPO42．5g／L、KCl 1．1g／L、NaCl 1．1g／L、MgSO4 0．15g／L、FeSO4·7H2O 5．0×10^-5g／L、EDTA 1．0g／L、酵母浸膏0．2g／L、初始pH值为7．0、温度为30℃、摇床转速为150r／min、发酵培养时间为3d。在该条件下，发酵液的表面张力最低，为29．3mN／m。[结论]菌株BS-2初步鉴定为枯草芽孢杆菌。

The study aimed to screen out piosurfactant-produeing bacteria from compost and optimize its culture condition. [ Method] The strains which could produce biosurfactant were screened from the agriculture aerobic compost samples with methods of enrichment culture and strain purification ect. and the cultural condition of strain was optimized through orthogonal test. [Result] A strain BS-2 that could produce biosurfactant was screened out from the agriculture aerobic compost, which could decreased the surface tension of broth below 40 mN/m and keep the same level under the temperature of 20 - 100 ℃ and pH of 6.0 - 9.5, showing its good surface tension and adaptability in conmposting environment. The optimized fermentation conditions were as follows： soluble starch 25.0 g/L, NH4NO3 8.0 g/L, KH2PO4 2.0 g/L, K2HPO4 2.5 g/L, KCl 1.1 g/L, NaCl 1.1 g/L, MgSO4 0.15 g/L, FeSO4·7H2O 5.0 × 10^-5 g/L, EDEA. 1.0 g/L, yeast paste 0.2 g/L, initial pH of 7.0, temperature of 30 ℃, rotation speed of 150 r/min, culture time of 3 d. Under this condition, the lowest surface tension of the broth was measured as 29.3 mN/m. [ Conclusion] The swain BS-2 was preliminarily identified as Bacillus subtilis.