Instituto Mexicano del Petróleo, Eje Central Lázaro Cárdenas, Norte 152 Col., San Bartolo Atepehuacan, Del. Gustavo A. Madero, C.P. 07730, México, Distrito Federal, Mexico.
Colloids Surf B Biointerfaces. 2011 Sep 1;86(2):384-9. doi: 10.1016/j.colsurfb.2011.04.026. Epub 2011 Apr 23.
The strain SmSA, identified as Serratia marcescens and known as a biosurfactant producer, was isolated from hydrocarbon contaminated soil from Veracruz, México. The interactions among the C/N, C/Mg and C/Fe ratios have not been examined for this microorganism. In this work was evaluated the effect of these nutrients at three levels using a mineral medium with glucose as the carbon source. A Box-Behnken experimental design was utilised to maximise biosurfactant production, which was assessed by oil spreading and surface tension tests. The treatment with C/N=5, C/Fe=26,000 and C/Mg=30 showed the best result since the surface tension was reduced to 30 mN m(-1). The multiple regression and response surface analyses indicated that the interaction between C/N and C/Mg had the utmost effect on the reduction of surface tension and biosurfactant production. The conditions of the best treatment were used to scale up biosurfactant production in a 3L bioreactor giving a yield of 4.1 gL(-1) of pure biosurfactant. It was found that the biosurfactant was mainly produced in the exponential phase and decreased the surface tension to 31 mN m(-1). The contact between the biosurfactant with heavy oil (15° API) increased its displacement from 9.3 to 18 cm.
从墨西哥韦拉克鲁斯污染的碳氢化合物土壤中分离出一株被鉴定为粘质沙雷氏菌（Serratia marcescens）的菌株 SmSA，它是一种生物表面活性剂产生菌。尚未研究过这种微生物的 C/N、C/Mg 和 C/Fe 比值之间的相互作用。在这项工作中，使用含有葡萄糖作为碳源的无机盐培养基，在三个水平上评估了这些营养物质的影响。利用 Box-Behnken 实验设计来最大化生物表面活性剂的产量，通过油扩散和表面张力测试来评估。当 C/N=5、C/Fe=26,000 和 C/Mg=30 时，处理效果最好，因为表面张力降低到 30 mN m(-1)。多元回归和响应面分析表明，C/N 和 C/Mg 之间的相互作用对表面张力和生物表面活性剂产量的降低有最大的影响。使用最佳处理条件在 3L 生物反应器中扩大生物表面活性剂的生产，得到 4.1 gL(-1)的纯生物表面活性剂产量。发现生物表面活性剂主要在指数期产生，并将表面张力降低至 31 mN m(-1)。生物表面活性剂与 15° API 重质油接触，增加了其从 9.3 到 18 cm 的位移。
