稠油降解微生物的筛选鉴定及其降解特性

Screening and identification of thick oil degrading microorganism and its degradation characteristics

从二连油田原油和油层水中筛选驯化出3株能够降解稠油的细菌DS1、DS2和DS3,通过16S rRNA基因序列比对发现DS1、DS2和DS3分别与溶血不动杆菌(Acinetobacter haemolyticus)、鹑鸡肠球菌(Enterococcus gallinarum)和耳炎短杆菌(Brevibacterium otitidis)相似度最高,分别为99%、99%和98%。研究结果表明,DS1对温度和pH有较强耐受性,DS3对盐度的适应性较好,2株菌最适的降解条件为温度35~40℃、盐度2%~5%(W/V)、pH为7~10。在5%的原油浓度下,复合菌对原油的30 d降解率达89.2%。经GC-MS分析,微生物降解作用后,除C29其他烃类几乎被全部降解。3株菌在7d内对500 g/L粘度为1 746 mPa·s(50℃)的稠油降粘率分别为49.1%、46.6%和49.0%,而复合菌对稠油的降粘效果高于单一菌株,其降粘率达到57.0%。

Three bacteria strains DS1,DS2 and DS3 with excellent degradation effect on thick oil were isolated from the thick oil and reservoir water in Erlian oil field. The 16S rRNA gene sequences alignment of DS1,DS2 and DS3 were most closely associated with Acinetobacter haemolyticus,Enterococcus gallinarum and Brevibacterium otitidis,and showed 99%,99% and 98% similarity respectively. The results showed that DS1 had a better adaptability to temperature and pH,while DS3 had a better adaptability to salinity. The optimum conditions for degradation of the two strains were 35 ~ 40℃,salinity 2% ~ 5%( W /V) and pH 7 ~ 10. The degradation rate of thick oil by mixed bacteria was 89. 2% after 30 days. GC-MS analysis revealed that hydrocarbons were almost exhausted through microbial degradation,except for C29. The viscosity reduction rates of thick oil( 500 g /L,1746mPa·s( 50℃)) were 49. 1%,46. 6% and 49. 0% by DS1,DS2 and DS3 respectively after 7 days. However,the viscosity reduction rate of thick oil was 57. 0% by mixed bacteria,which was significantly higher than the single strain.