生物破乳剂产生菌的筛选及其方法研究

Isolation of Strains Producing Bio-demulsifiers and Comparison of Screening Methods

摘要:

针对生物破乳剂产生菌筛选难的问题, 采用显色法、溶血细胞测试法、表面张力测定法和排油圈法从6种不同菌源对生物破乳菌产生菌进行了筛选。通过试验筛选得到了17株生物破乳剂产生菌, 其中24h内破乳率高于70%的破乳菌有5株; 油田含油污泥、采油废水生物处理污泥和污水处理厂剩余污泥是筛选破乳菌的较好的菌源; 显色法、溶血圈法存在检测范围的局限性; 表面张力测定法和排油圈法是最为简易和准确的生物表面活性剂产生菌的筛选方法, 采用模型乳状液对生物破乳剂产生菌进行筛选最为直接和准确, 但工作量大、所需时间长, 因此在筛选高效破乳菌时, 建议采用表面张力、排油圈法进行初筛, 而后通过模型乳状液破乳进行验证。

Abstract:

Four screening methods, colorimetric assay, blood-plate hemolysis method, surface tension activity and oil spreading technique were introduced to isolate strains producing bio-demulsifiers from 6 different bacteria source samples. The results of various screening methods were evaluated in this paper. Seventeen demulsifying strains were obtained, which are qualified in demulsification test of kerosene model emulsions. Among them, 5 strains showed high demulsifying ability, achieving 70% plus demulsifying ratio within 24 hours. Petroleum-contaminated soil, excess sludge from biological process treating oilfield produced water and sludge from municipal wastewater treatment plant were the best among all tested sources. Due to the determination limit, the colorimetric assay and blood-plate hemolysis method are not competent to screen bio-demulsifiers strains. The measurement of surface tension and oil spreading method were easy but accurate methods to isolate bio-demulsifiers strains. Although demulsification test of model emulsion is an effective technique to target strains with the capability of breaking emulsions, it is sophisticated and time-con- suming. Thus it is recommended to use surface tension and oil spreading methods in pre-screening and validate the results in demulsification test with kerosene model emulsions.