Hou Ning, Feng Fengzhao, Shi Yan, Cao Huiming, Li Chunyan, Cao Zhi, Cheng Yi
College of Resources and Environment, Northeast Agricultural University, Harbin, 150030, China.
Environ Sci Pollut Res Int. 2014 Sep;21(17):10386-98. doi: 10.1007/s11356-014-2931-7. Epub 2014 Apr 29.
A highly efficient demulsifying strain, LH-6, was isolated from petroleum-contaminated soil and identified as Bacillus cereus by 16S rDNA gene analysis. It achieved 95.61 and 95.40 % demulsifying ratios within 12 h for water-in-oil (W/O) and oil-in-water (O/W) model emulsions, respectively. Fourier transform infrared spectroscopy (FT-IR) and thin-layer chromatography (TLC) detections indicated that the LH-6's extracellular biodemulsifiers were different types of lipopeptides for the W/O and O/W emulsions. Optimization of the culture medium composition was conducted to improve the biosynthesis and demulsifying efficiency of the biodemulsifier. The optimal carbon source was liquid paraffin, while waste frying oil could also be an alternative carbon source. The optimal nitrogen sources were ammonium sulfate and yeast extract. To further enhance the biodemulsifier efficiency, the optimal cultivation conditions were determined using response surface methodology (RSM) based on central composite rotation design (CCRD). Using the optimized cultivation conditions, the demulsifying ratios increased to 98.23 and 97.65 % for the W/O and O/W model emulsions, respectively.
从石油污染土壤中分离出一种高效破乳菌株LH-6，通过16S rDNA基因分析鉴定为蜡样芽孢杆菌。对于油包水（W/O）和水包油（O/W）模型乳液，它分别在12小时内实现了95.61%和95.40%的破乳率。傅里叶变换红外光谱（FT-IR）和薄层色谱（TLC）检测表明，LH-6的细胞外生物破乳剂对于W/O和O/W乳液是不同类型的脂肽。对培养基成分进行了优化，以提高生物破乳剂的生物合成和破乳效率。最佳碳源是液体石蜡，而废弃煎炸油也可以作为替代碳源。最佳氮源是硫酸铵和酵母提取物。为了进一步提高生物破乳剂的效率，基于中心复合旋转设计（CCRD），采用响应面法（RSM）确定了最佳培养条件。使用优化后的培养条件，W/O和O/W模型乳液的破乳率分别提高到了98.23%和97.65%。
