解烃菌BD-2产表面活性剂及其稳定性研究

The Properties and Stability of Biosurfactant Produced by a Hydrocarbon-degrading Strain BD-2

生物表面活性剂是一种多功能物质,具有毒性低、可生物降解、环境相容性好等特点,是化学表面活性剂的生态替代品。该研究以产表面活性剂解烃菌BD-2为研究对象,分析菌株BD-2生长与表面活性剂的形成关系,采用单因素实验优化培养基组成和发酵条件,考察环境条件对生物表面活性剂稳定性的影响。结果表明,解烃菌BD-2产表面活性剂的量与菌体生长相关,最适碳氮源为葡萄糖和硝酸铵,Fe^(^(2+))对菌株BD-2产生物表面活性剂无显著影响,Mn^(2+)对菌株BD-2产生物表面活性剂有较好的促进作用。菌株BD-2产表面活性剂的最适发酵条件为:pH 7、温度30℃、盐浓度1%,在此条件下,生物表面活性剂产量可显著提高至2.6 g/L,同时,发酵液的表面张力由68.3 mN/m降低到26.80 mN/m,乳化指数(E24)达到92.8%。此外,菌株BD-2产生的生物表面活性剂在较宽的温度、pH和盐浓度范围内具有良好的稳定性。

Biosurfactants are multifunctional substances characterized as lower toxicity,biodegradable materials,environ⁃mentally compatible,making them ecological alternatives to chemical surfactants.In this study,the surfactant-producing hy⁃drocarbon-dissolving bacterium BD-2 was used to analyze the relationship between the growth of strain BD-2 and the forma⁃tion of surfactants,and single factor experiment was used to optimize the medium composition and fermentation conditions,and to investigate the effect of environmental conditions on the stability of biosurfactant.The results showed that the amount of surfactant produced by the hydrocarbon solubilizing bacterium BD-2 was related to the growth of the bacterium,and the optimal carbon and nitrogen sources were glucose and ammonium nitrate.Fe^(^(2+))had no significant effect on the surfactant produced by strain BD-2,and Mn^(2+)had a better promotion effect on the surfactant produced by strain BD-2.The optimum fermentation conditions for surfactant production by strain BD-2 were pH 7,temperature 30℃ and salt concentration 1%,under which the biosurfactant production could be significantly increased to 2.6 g/L,and meanwhile,the surface tension of the fermentation broth was reduced from 68.3 mN/m to 26.80 mN/m,and the emulsification index(E24)reached 92.8%.In addi⁃tion,the biosurfactant produced by strain BD-2 had good stability over a wide range of temperature,pH and salt concentration range with good stability.