一株耐温耐盐烃降解菌Geobacillus sp. XDF-4性能

Characterization of a thermophilic and halotolerant strain Geobacillus sp. XDF-4

从大庆油田龙虎泡区块采油地层水中分离得到一株性能很好的耐盐耐温的兼性烃降解菌XDF-4,经形态观察、生理生化实验和16S rDNA基因序列分析,初步鉴定为地芽孢杆菌Geobacillus sp.。该菌在45~75℃、pH6.5~9.0、盐的质量分数0~10%下生长良好,其最适生长温度为65℃,最适盐的质量分数为3.0%。研究发现,该菌株能以原油为唯一碳源生长并合成生物表面活性剂,发酵7d,其发酵液表面张力从68.59mN.m-1降到29.58mN.m-1。薄层色谱和显色反应表明,XDF-4产出的表面活性剂主要包含：糖类50.26%（质量）、脂类28.47%（质量）、蛋白质15.35%（质量）;其临界胶束浓度为22mg·mL-1。GC气相色谱和族组分柱色谱分析表明,烃降解菌Geobacillussp.XDF-4作用后,原油轻质组分含量明显增加,重质组分含量降低。物理模拟实验表明,该菌可在一次水驱基础上进一步提高采收率5.69%,可有效应用于高温高盐油藏微生物驱现场实验。

A strain XDF-4 was obtained by isolation from stratum water of oil recovery in Longhupao block of Daqing oil field,and identified as Geobacillus sp.by morphological observation,physiological and biochemical test and 16S rDNA gene sequence analysis.It grows well at 45—75℃,pH 6.5—9.0 and salt concentration 0—10%,and the optimum conditions was 65℃ and salt concentration 3%.It was found that XDF-4 could utilize crude oil as sole carbon source to synthesize biosurfactant at high temperature and salinity,which could lead to decrease in surface tension of the culture medium from 68.59 mN·m-1 to 29.58 mN·m-1 after 7 d zymolysis.The results from thin-layer chromatography and chromogenic reaction showed that the biosurfactant produced by XDF-4 involves three main compounds：glycosides 50.26%（mass）,lipids 28.47%（mass）and protein 15.35%（mass）,and its critical micell concentration（CMC）was 22 mg·mL-1.The data from gas chromatography and group composition analysis revealed that light components of the crude oil increase obviously and the mass portions decrease after XDF-4 strain metabolism.Asi mulation study for actual environment in petroleum reservoirs showed that the strain XDF-4 could increase the oil recovery by 5.69 % on the basis of one water drive and have a promising prospect in MEORtechnology for the field applicationin the high temperature and salinity reservoir.