高效石油降解菌的筛选及其降解特性

Isolation of Petroleum-degrading Strains and Their Degrading Characteristics

从辽河油田和大庆油田石油污染土壤中分离筛选出两株高效石油降解菌L10和D6菌株,经形态观察、生理生化反应,确定此两株菌分别为芽孢杆菌属中的枯草芽孢杆菌(Bacillus subtilis)和地衣芽孢杆菌(Bacillus licheniform is)。采用室内盆栽培养方法,研究了石油烃的浓度和性质对两菌株降解活性的影响。结果发现,土壤中石油烃的含量和处理时间均影响微生物的降解效果,在处理10d时,石油烃的去除率随着污染强度的增加而降低;随着处理时间的延长,微生物适应环境后,在石油烃含量为0.5%～2.0%时,石油烃的去除率随着浓度的增加而升高,在石油烃含量为2.0%～10.0%时,石油烃的去除率随着浓度的增加而降低;石油烃的性质影响菌株的生物活性,L10和D6两菌株对稀油的去除效果明显高于对稠油的去除效果,各组分的去除率依次为烷烃>芳烃>胶质沥青质,两菌株对不同性质的石油烃中的烷烃、芳烃和胶质沥青质的去除率不同。

Petroleum-degrading strains L10 and D6 were obtained by selective enrichment culture from eight contaminated soil samples collected from Liaohe and Daqing Oil Fields. The tests in shaking flasks showed that they could degrade petroleum hydrocarbon well and the removal rates could reach 39.5% and 47.9% at 30 d. According to morphologic observation, physiological and biochemical characteristics, they were identified as Bacillus subtilis and Bacillus licheniformis respectively. Their removal abilities to petroleum were affected by petroleum＇s concentrations and properties. At 10 d, the removal rates reduced with increasing concentrations of petroleum. With the treatment time prolonged, the removal rates increased at concentrations 0.5%～2.0% and reduced when the concentrations were 2.0%～10.0%, implying that appropriate petroleum concentration stimulated the activities of microbes, but higher petroleum concentration restrained their activities. The degradation rates of thin-oil by L10 and D6 were higher than those of viscous-oil under the same conditions. The removal rates of aromatics, pectin and asphalt by L10 and D6 were different due to the petroleum properties. The order of removal rate for each component was alkanes〉 aromatics〉pectin and asphalt, with the removal rates being 62.96% ～78.67%, 16.76%～33.92% and 3.78%～15.22%, respectively. So, it is very important that petroleum properties and microbes characteristics are considered in bioremediation of contaminated soil.