脂肽-糖脂混合型生物表面活性剂的性能及助剂

Characterization of a lipopeptide-glycolipid blend biosurfactant and the effect of alcohol cosurfactant

分离提取了枯草芽孢杆菌Bacillus subtilis THY-8发酵产物中的生物表面活性剂，采用飞行时间质谱鉴定为鼠李糖脂和表面活性素、芬芥素等的混合物。考察了该混合型生物表面活性剂的性能，研究了其对油砂原油的驱油效率，并探索了合适的助剂种类及配伍浓度。结果表明，THY-8所产的脂肽-糖脂混合型生物表面活性剂具有良好的表面活性、热稳定性和乳化性，pH值为5.5时表面张力为27.59 mN/m，临界胶束浓度为15 mg/L；在70℃放置5天，表面张力基本不变；可将液体石蜡乳化形成粒径10～30μm的乳液。正辛醇助剂与该混合生物表面活性剂复配后界面张力降低到10-3 mN/m，驱油效率提高3.2倍。含0.9 g/L生物表面活性剂的发酵液驱油效果与正辛醇-生物表面活性剂复配体系相当。

Biosurfactants （BS） produced by Bacillus subtilis THY-8 were extracted and identified as a blend of rhamnolipid,surfactin and fengycin,etc,by MALDI-TOF Mass Spectrometry. The blend BS remained stable when stayed at 70℃ for 5 days;and the surface tension and critical micelle concentration were 27.59 mN/m and 15 mg/L at pH5.5,respectively. When treated by BS,the liquid paraffin was emulsified into small drops in the diameter of 10-30μm,and high recovery efficiency of crude oil from oil-sand was also obtained. Cosurfactants of BS were explored and 1-octanol was determined to be one of the optimal ones. The 1-octanol/BS complex reduced the interfacial tension of crude oil/mineralized water to 10-3 mN/m together with 3.2-fold-enhanced oil recovery efficiency. Equivalent oil washing capability was also obtained by fermentation broth with as low as 0.9 g/L BS, revealing that potential application of BS in enhanced oil recovery is promising.