假单胞菌AB93066产鼠李糖脂发酵条件的优化

通过单因素实验和正交实验对铜绿假单胞杆菌AB93066产鼠李糖脂(RL)的摇瓶发酵培养基配方和产生规律进行了研究。结果表明,最佳培养基配方为:ρ(酵母膏)=0.2 g/L,ρ(豆油)=120 g/L,ρ(NaNO3)=6.5 g/L,ρ(KH2PO4)=1.0 g/L,ρ(Na2HPO4.12H2O)=1.0 g/L,ρ(MgSO4.7H2O)=0.1 g/L,ρ(FeSO4.7H2O)=0.2 g/L,pH=6.0。RL的收获期在发酵后156~168 h最佳。发酵生产RL的扩大实验表明,在最优发酵条件下RL的产量可达56 g/L以上,提取后的RL可将去离子水的表面张力降至29.01 mN/m。用高效液相色谱/质谱联用仪进一步分析了所提取的RL的组成,它分别为二鼠李糖脂(R1)和单鼠李糖脂(R2)两种同系物。R1和R2的表观临界胶束浓度(CMC)分别为0.03 mmol/L和0.04 mmol/L。

Optimization on Fermentation Conditions of Rhamnolipids Production by Pseudomonas AB93066

The optimized conditions for fermentation medium and the production regulation of rhamnolipids(RL) produced by pseudomonas aeruginosa AB93066 were as follows.The composition of the medium was ρ(yeast)=0.2 g/L,ρ(bean oil)=120 g/L,ρ(NaNO3)=6.5 g/L,ρ(KH2PO4)=1.0 g/L,ρ(Na2HPO4·12H2O)=1.0 g/L,ρ(MgSO4·7H2O)=0.1 g/L and ρ(FeSO4·7H2O)=0.2 g/L,pH=6.0.The time range for harvesting RL was between 156 h and 168 h after fermentation.Scale-up production experiment indicated that RL yield was 56 g/L and more under the optimal conditions.Surface tension measurements showed that the extracted RL could decrease the surface tension of deionized water to 29.01 mN/m.Dirhamnolipid(R1) and monorhamnolipid(R2) were separated and identified from the extracted RL using liquid chromatography/mass spectrometry.The apparent critical micelle concentration of R1 and R2 were 0.03 mmol/L and 0.04 mmol/L,respectively.