pH对破乳菌Alcaligenes sp. S-XJ-1破乳性能的影响

Influence of pH on Emulsion Breaking Performance of a Demulsifying Strain Alcaligenes sp. S-XJ-1

摘要:

从受石油污染的土壤中筛选出一株破乳菌Alcaligenes sp. S-XJ-1, 该菌在初始pH 6.0?11.0均可生长, 其最适初始pH为10.0。在初始pH 10.0条件下培养, 破乳菌产量最高可达4.8 g/L, 菌悬液投加量为1000 mg/L时, 24 h破乳率在85%以上。同时, 该培养条件下得到的生物破乳菌细胞表面疏水性最大, 对碳氢化合物的吸附能力达72.7%, 接触角达115°。采用稳定性分析仪分别对pH 7.0和pH 10.0条件下培养得到的菌体的破乳效果进行分析, 结果发现与初始pH 7.0相比, 初始pH 10.0培养得到的破乳菌可以加速分散相粒径的增大, 最终使乳状液破乳速率大幅提高。

Abstract:

One demulsifying strain of Alcaligenes sp. S-XJ-1, isolated from the oil-contaminated soil, could grow at initial cultivation pH ranging from 6.0 to 11.0 and the optimum pH was observed at 10.0. Cultivated at initial pH 10.0, the biomass yield reached highest at 4.8 g/L and the emulsion breaking ratio achieved over 85% within 24 h when the biodemulsifier was dosed at 1000 mg/L. Meanwhile, this demulsifying strain S-XJ-1 had a higher cell surface hydrophobicity with ratio of microbial adhesion to hydrocarbon at 72.7% and water contact angle at 115° when it was cultivated at initial pH 10.0. To compare the demulsification process of demulsifiers produced at pH 7.0 and pH 10.0, kerosene-water model emulsion (W/O) mixed with the demulsifier was analyzed using Turbiscan method. Compared with the biodemulsifier produced under initial pH 7.0, the biodemulsifier produced at initial pH 10.0 remarkably increased the particle size of the dispersed phase, and then greatly improved the emulsion breaking rate.