Synthesis and Interfacial Properties of Bio-Based Zwitterionic Surfactants Derived from Different Fatty Acids in Non-Edible Vegetable Oils

Waste cooking oils and non-edible vegetable oils are abundant and renewable resources for bio-based materials which have showed great potential applications in many industries.In this study,five fatty acids commonly found in non-edible vegetable oils,including palmitic acid,stearic acid,linoleic acid,linolenic acid,ricinoleic acid,and their mixtures,were used to produce bio-based zwitterionic surfactants through a facile and high-yield chemical modification.These surfactants demonstrated excellent surface/interfacial properties with the minimum surface tensions ranging from 28.4 mN/m to 32.8 mN/m in aqueous solutions.The interfacial tensions between crude oil and surfactant solutions were remarkably reduced to lower values ranging from 0.0028 mN/m to 0.1983 mN/m without the aid of extra alkali,which particularly implied a great potential application in enhanced oil recovery.Meanwhile,these bio-based surfactants also showed good wetting properties(contact angles of~51°comparing with that of double distilled water,92.04°)and appropriate predicted biodegradability(degradation order of“weeks”for bio-based surfactants synthesized from saturated fatty acids,and“months”for those synthesized from unsaturated fatty acids).Bio-based surfactants synthesized from unsaturated fatty acids showed better interfacial properties in reducing interfacial tension between crude oil and formation water.The bio-based surfactants presented in this study are alternative substitutes for traditional petroleum-based surfactants in various surfactant application fields.

Effect of the microbial lipopeptide on tumor cell lines: apoptosis induced by disturbing the fatty acid composition of cell membrane

Microbial lipopeptides play an important role in apoptosis induction of tumor cells.However,there is little knowledge about the relationship between apoptosis induction and membrane fatty acids.The present study focused on the effects of lipopeptides produced by Bacillus subtilis HSO121 on Bcap-37 cell lines.3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl(MTT)colorimetric assay and surface tension measurements,showed that the critical micelle concentration(CMC)was a critical level for the inhibitory activity of lipopeptides on the growth of Bcap-37 cells.Under the CMC,the order of least to greatest cytotoxicity effect on cancer cell lines by lipopeptides is C13-lipopeptide<C14-lipopepitde<C15-lipopeptide.Above CMC,all lipopeptides directly exert cytolytic activity.The flow cytometric analysis and Hoechst33258 staining experiments confirmed the apoptosis of Bcap-37 cell lines induced by lipopeptides in a dose-dependent manner.This apoptosis was associated with a significant decrease of the unsaturated degree of the cellular fatty acids of Bcap-37 cell lines due to the changes in the cellular fatty acids composition induced by the lipopeptide treatment.These results indicated that disturbance of the cellular fatty acid composition of breast cancer cell lines were related to in the cell apoptosis.Furthermore,significant difference in IC50 values of tumor cells and normal cell showed that the lipopeptide exerted selective cytotoxicity on the cancer cells.Thus HSO121 lipopeptides may have potential applications as an anticancer leads.