一株可乳化降解原油的Compostibacillus的分离及特性

Isolation and characterization of a hydrocarbon-degrading strain of Compostibacillus

【背景】通过实施多轮次微生物采油,华北油藏产出液菌浓达到了106个/mL以上,油藏内部已经形成了较稳定的微生物发酵场,从其中筛选出能够乳化降解原油的微生物,并在地面对其进行扩大培养,然后再应用到微驱油藏,以进一步提高微生物采油实施效果。【目的】筛选乳化降解原油性能良好的菌株,对其进行多相分类学鉴定和性能评价。【方法】利用原油为底物筛选乳化降解性能良好的菌株,通过形态特征观察、生理生化测定、16S rRNA基因序列分析等确定菌株的分类地位。通过乳化能力、降解率等方法确定菌株的原油乳化降解特性。【结果】从华北油田采集的地层水样品中分离得到一株乳化原油的菌株BLG74,经多相分类鉴定表明其是土壤堆肥芽孢杆菌(Compostibacillus humi)的新菌株,亲源性99.6%。该菌株的生长温度为30?60℃(最适温度45℃),pH 6.5?9.5(最适pH 7.0),NaCl浓度0%?7%(质量体积比)。菌株BLG74在玉米浆培养基中培养,其发酵液的表面张力为56.3 mN/m,乳化力约95%,在初始原油质量浓度0.5%、温度45℃的条件下培养20 d,对原油的降解率可达40.8%。【结论】菌株BLG74是可乳化降解原油的新成员,其在热盐条件下乳化降解原油的特性在石油开采中有一定的潜力。

[Background]By implementing multiple cycles of microbial oil recovery,the reservoir produced liquid bacteria concentration reached more than 106 CFU/mL,forming a stable microbial fermentation field in the reservoir.To further improve the effect of microbial oil recovery,the crude oil-emulsifying and hydrocarbon-degrading bacteria from the reservoir was selected to cultivate for microbial oil recovery application in the reservoir.[Objective]The strains with good performance of crude oil-emulsifying and hydrocarbon-degrading capacity are screened out to carry out multiple taxonomic identification and performance evaluation.[Methods]Crude oil was chosen as substrate for strains selection.Through morphological observation,biochemical and physiological characteristics and 16S rRNA gene sequence,the taxonomic position of the strain BLG74 was identified.The crude oil-emulsifying and hydrocarbon-degrading capacity of the strain BLG74 were investigated by emulsifying ability and degrading rate.[Results]Strain BLG74 was selected from the production water sample of Huabei oil field.16S rRNA gene sequence analysis showed that the strain belonged to the genus Compostibacillus and most closely related to Compostibacillus humi with identity of 99.6%.Its growth environment has a pH of 6.5 to 9.5(optimum at pH 7.0),a temperature of 30℃ to 60℃(optimum at 45℃)and a salinity of 0%to 7%.Strain BLG74 was cultured in crude oil degradation medium.The surface tension of the fermentation broth was 56.3 mN/m,and the emulsifying capacity was about 95%.It was cultured for 20 days under the initial crude oil mass concentration of 0.5%and temperature of 45℃,resulting in the degradation rate of up to 40.8%.[Conclusion]Strain BLG74 is a new member of bacteria capable of emulsifying and degrading crude oil,presenting a remarkable potential in microbial enhanced oil recovery with its crude oil-emulsifying and hydrocarbon-degrading capacity under hot salt conditions.