利用不同组分原油逐级驯化筛选高效石油烃降解混菌

利用不同组分原油逐级驯化的方法对克拉玛依油田的石油污染土样进行石油烃降解混菌的富集驯化，得到一组对稀油和稠油均具有高效降解能力的混菌M3。与采用单一原油驯化方法相比，混菌M3对稀油和稠油的降解率分别提高了12.5%和22%。该混菌具有较强的产表面活性剂的能力，能够使发酵液的表面张力从69.8 mN·m-1降至27.9 mN·m-1。通过混菌M3的生长条件优化实验得出：在温度30 ℃、pH 7~8、盐度1%、氮源选择尿素的条件下，混菌M3对原油的降解率最高。通过考察混菌M3在污染土壤中对原油的降解效果，发现：在修复期间，土壤脱氢酶呈先升高后降低的趋势；混菌M3可使饱和烃组分增加，并使芳香分、胶质和沥青质组分降低，对重质组分具有较好的降解效果。混菌M3的加入改变了原油性质，促进了土壤中原油的降解，经过56 d修复，土壤中原油降解率达到55.3%。

Stepwise domestication and screening of high effective petroleum hydrocarbon degrading bacteria by using crude oil with different components

In this study, the petroleum hydrocarbon degrading bacteria were enriched and domesticated from the oil contaminated soil samples collected from Karamay oil field through a stepwise method using thin oil and heavy oil with different components, and a group of mixed bacteria M3 with high degradation ability for both thin oil and heavy oil was obtained. The corresponding degradation rates increased by 12.5% and 22%, respectively, in comparison with the traditional enrichment method using single crude oil. The mixture has a strong ability to produce biological surfactants, and can reduce the surface tension of the solution from 69.8 mN·m-1 to 27.9 mN·m-1. By optimizing the growth conditions of M3, the highest degradation rate of crude oil was obtained at the temperature of 30 ℃, pH 7~8, salinity of 1% and a nitrogen source of urea. The effect of M3 on degrading crude oil in contaminated soil showed that the soil dehydrogenase increased, and then decreased during the period of remediation. The addition of mixed bacteria M3 resulted in the change of crude oil properties, in which the saturated hydrocarbon components increased, aromatic hydrocarbons, colloid and asphaltene components decreased. The mixed M3 promoted the degradation of crude oil in soil with the corresponding degradation rate of 55.3% after 56 d remediation.