从甘肃玉门油田鸭儿峡油藏样品中分离到3株可降解原油并具有很好乳化活性的嗜热菌株，经16S rRNA基因序列分析和生理生化鉴定，3株分离菌分别为短小芽孢杆菌（Brevibacillus sp. XS1）和白色土芽孢杆菌（Geobacillus pallidus XS2，XS3）。3株分离菌均可在50℃高温下生长，其中菌株XS2的最适生长温度为60℃，在pH值为5.5—9.5范围内均可生长，有良好适应性，盐浓度对菌株生长影响不大。菌株XS2同时还具有很好的乳化活性和乳化稳定性，在100℃高温，20%盐浓度下，乳化活性均无明显变化。通过对原油降解过程中色谱特征分析，菌株XS2不仅可降解原油组分中的轻质组分，而且还能很好地降解原油中重质组分，提高原油流动性，原油品质也得到大大改善，可见菌株XS2是一株潜在驱油微生物，在微生物采油中具有较好的应用前景。

Three thermophilic bacteria were isolated from the crude oil contaminated soil samples gathered from Yaerxia oil reservoirs of Yumen oilfield in Gansu Province. According to their 16S rRNA gene analyses, and the physiological properties, the isolated XS1 was identified as Brevibacillus sp; and the isolated XS2 and XS3 were identified as Geobacillus pallidus. The three isolates could degrade crude oil and had effective emulsification activity. All the isolates can grow at a high temperature, with the optimal growth temperature of XS2 being 60℃, and have a wide adapt-ability to pH, in the range of 5.5—9.5. NaCl concentration has no obvious effect on the growth of three strains. Meanwhile, XS2 has an effective emulsification activity; and the emulsification activity has no apparent change at 100℃ and under 20% salinity conditions. The analysis of chromatogram characteristic changes of crude oil during biodegradation process shows that the strain XS2 can degrade not only the light-weight components of crude oil, but also its heavy-weight components, it enhances the fluidity of crude oil, and the quality of crude oil is also improved. It will have a good prospect in microbial enhanced oil recovery.