一株石油烃降解菌的细胞疏水性及其乳化性质

Cell-surface hydrophobicity and emulsification of a hydrocarbon-degrading strain

摘要:

【目的】从新疆油田石油污染土壤中分离到一株在25 °C条件下利用烃类产生生物表面活性剂的菌株红球菌(Rhodococcus sp.) HL-6, 对其菌体细胞疏水性及所产表面活性剂进行研究。【方法】通过细胞粘附性、表面张力及乳化活性测定对菌株所产表面活性剂进行性质研究。【结果】菌株HL-6在亲水性和疏水性基质中均能产生生物表面活性剂, 在疏水性基质中可以将培养液表面张力由初始的62.487 mN/m降到30.667 mN/m, 培养液在pH 6?9及NaCl浓度1%?5%范围内乳化效果良好, 在4 °C到55 °C范围内乳化效果均为100%, 菌株对柴油的耐受能力很高, 在30%柴油浓度下依然生长良好并且有44%的乳化活性。【结论】HL-6菌株的细胞表面具有很强的疏水性, 这有助于菌体细胞对烃类的摄取。该菌株能够利用烃类基质生产生物表面活性剂, 可以明显降低培养液表面张力并且对石油烃具有良好的乳化作用。说明菌株HL-6能够适应海洋滩涂石油污染的环境, 并可用于严重石油污染区域的生物修复。

Abstract:

[Objective] A hydrocarbon-degrading strain HL-6 was isolated from oil contaminated soil of Xinjiang Oil Field and identified as Rhodococcus sp., which could use hydrocarbon as sole carbon source to produce biosurfactant. The bacterial cell hydrophobicity and biosurfactant production were studied. [Methods] Through cell adhesion, surface tension and emulsifying activity, the biosurfactant was studied. [Results] The strain could produce biosurfactant in both hydrophilic and hydrophobicsubstrate. The surface tension was reduced from the initial 62.487 mN/m to 30.667 mN/m when substrate was hydrophobic. Diesel could be well emulsified by strain HL-6 and the emulsion toleratedsalinity, alkaliand temperature. In addition, strain HL-6 could grow well in medium containing 30% of diesel and had 44% emulsification. [Conclusion] Strain HL-6 had a strong cell-surface hydrophobicity, which contributed to uptake hydrocarbons. This strain could use hydrocarbon to produce biosurfactant, significantly reduce the culture surface tension and had good emulsification of petroleum hydrocarbons. So strain HL-6 was able to adapt to the environment of the marine shoals oil pollution, especially serious oil pollution.