Liu Qing-kun, Wang Jun, Li Guo-qiang, Ma Ting, Liang Feng-lai, Liu Ru-lin
The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, The Key Laboratory of Microbial Functional Genomics of Tianjin, College of Life Sciences, Nankai University, Tianjin 300071, China.
Huan Jing Ke Xue. 2008 Dec;29(12):3554-60.
A thermophilic Geobacillus strain DM-2 from a deep-subsurface oil reservoir was investigated on its capability of degrading crude oil under various conditions as well as its characters on degrading hydrocarbons in optimal conditions. The results showed that Geobacillus strain DM-2 was able to degrade crude oil under anoxic wide-range conditions with pH ranging from 4.0 to 10.0, high temperature in the range of 45-70 degrees C and saline concentration ranging from 0.2% to 3.0%. Furthermore, the optimal temperature and pH value for utilizing hydrocarbons by the strain were 60 degrees C and 7.0, respectively. Under such optimal conditions, the strain utilized liquid paraffine emulsified by itself as its carbon source for growth; further analysis by gas chromatography (GC) and infrared absorption spectroscopy demonstrated that it was able to degrade n-alkanes (C14-C30), branched-chain alkanes and aromatic hydrocarbons in crude oil and could also utilize long-chain n-alkanes from C16 to C36, among of which the degradation efficiency of C28 was the highest, up to 88.95%. One metabolite of the strain oxidizing alkanes is fatty acid.While utilizing C16 as carbon source for 5 d, only one fatty acid-acetic acid was detected by HPLC and MS as the product, with the amount of 0.312 g/L, which indicated that it degraded n-alkanes with pathway of inferior terminal oxidation,and then followed by a beta-oxidation pathway. Due to its characters of efficient emulsification, high-performance degradation of hydrocarbons and fatty-acid production under high temperature and anoxic condition, the strain DM-2 may be potentially applied to oil-waste treatment and microbial enhanced heavy oil recovery in extreme conditions.
对从深层地下油藏中分离得到的嗜热地芽孢杆菌菌株DM-2在不同条件下的原油降解能力以及在最佳条件下的烃类降解特性进行了研究。结果表明，地芽孢杆菌菌株DM-2能够在缺氧的宽范围条件下降解原油，pH范围为4.0至10.0，高温范围为45-70℃，盐浓度范围为0.2%至3.0%。此外，该菌株利用烃类的最佳温度和pH值分别为60℃和7.0。在这种最佳条件下，该菌株利用自身乳化的液体石蜡作为生长的碳源；通过气相色谱（GC）和红外吸收光谱进一步分析表明，它能够降解原油中的正构烷烃（C14-C30）、支链烷烃和芳烃，还能够利用C16至C36的长链正构烷烃，其中C28的降解效率最高，可达88.95%。该菌株氧化烷烃的一种代谢产物是脂肪酸。以C16为碳源培养5 d时，通过高效液相色谱（HPLC）和质谱（MS）检测到仅有一种脂肪酸产物乙酸，含量为0.312 g/L，这表明它通过次末端氧化途径降解正构烷烃，然后遵循β-氧化途径。由于其在高温和缺氧条件下具有高效乳化、高性能烃类降解和脂肪酸产生的特性，菌株DM-2可能潜在地应用于油废物处理和极端条件下的微生物强化稠油开采。
