嗜热耐盐烃降解菌Geobacillus sp.WJ-2降解原油性能研究

以液蜡为唯一碳源,从大庆油田龙虎泡区块采油污水样中分离到一株高效嗜热耐盐的兼性烃降解菌WJ-2,经形态观察、生理生化实验和16S rRNA基因序列分析,初步鉴定为地芽孢杆菌Geobacillus sp..在有氧或者厌氧条件下,该菌均在45～75℃和0～10％ NaCl溶液中生长良好,其最适生长温度为65℃,最适盐的质量分数为3.0％；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,生物表面活性剂产量在好氧条件和厌氧条件下分别为19.89 g/L和11.69 g/L.薄层层析和显色反应表明WJ-2产出的表面活性剂组成在好氧和厌氧条件下不相同.经GC气相色谱和族组分柱层析对菌株WJ-2在好氧和厌氧降解下原油组分分析结果表明:该菌在好氧下优先降解较轻组分,在厌氧条件下优先降解重质组分,原油黏度分别降低71.57％和77.45％,凝固点分别降低5℃和8℃.在好氧和厌氧条件下该菌可在一次水驱基础上分别进一步提高采收率6.96％和6.42％,可有效应用于高温高盐油藏微生物驱现场试验.

Oil-degrading characterization of thermophilic and halotolerant strain Geobacillus sp.WJ-2

Strain WJ-2 which was identified as Geobacillus sp.by morphology,physiological and biochemical identification and analysis of 16S rDNA sequencing was characterized to degrade crude oil and produce biosurfactant at high temperature and salinity.It could grow at 45-75 ℃ and 0-10%(mass fraction) of NaCl,and the optimal temperature and NaCl concentration is 65 ℃ and 3.0%,respectively.Under aerobic or anaerobic condition,the strain could utilize crude oil as sole carbon source to synthesize biosurfactant that the yield is 19.89 g/L and 11.69 g/L,respectively.Based on thin layer chromatography and chromogenic reaction,the purified biosurfactant is extracted from two conditions contain different compounds.Gas chromatography and group composition analysis reveal that the strain WJ-2 has a preference of utilizing light components under aerobic condition,degrading heavy components under anaerobic condition and decreasing the viscosity by 71.57% and 77.45% and freezing point of crude oil by 5 ℃ and 8 ℃,respectively.Sand cores were used to simulate the actual environment in Daqing petroleum reservoirs.The results show that the oil recovery of strain WJ-2 under aerobic and anaerobic condition increases by 6.46% and 5.92%,respectively.