多环芳烃降解菌的筛选及其降解性能的强化

Screening and degrading capacity improvement of polycyclic aromatic hydrocarbons degrading bacterium

为提高煤化工废水生化处理系统中微生物对多环芳烃降解效率,从生化出水中筛选了一株以菲为唯一碳源的高效降解菌,并进行了16Sr DNA基因序列鉴定。通过考察降解菌的生理生化特性和粘附特性,确定了降解菌的最适生长条件,并探讨了腐植酸对降解菌疏水性的影响及对细菌降解性能的增强作用。研究结果表明:该菌为红球菌属,命名为Rhodococcus sp.XY916,其最适生长pH为弱碱性,可耐受矿化度范围为0~20 000 mg/L,可在菲含量为120 mg/L的环境中正常生长。低浓度的腐植酸能够提高XY916的疏水性,同时又能增大菲的表观溶解度,进而提高XY916与菲的接触面积,促进菲的降解,降解率可达95.3%。

In order to improve the degrading efficiency of polycyclic aromatic hydrocarbons（ PAHs） in biochemical treatment system of coal chemical wastewater,a highly efficient phenanthrene degrading strain with phenanthrene as the sole carbon source was isolated from biochemical effluent and identified based on 16 Sr DNA sequence.By means of examination of the physiological and biochemical characteristics of the degrading bacterium,the optimum growth conditions of the degrading bacterium were determined. Besides,effects of humic acid on strain hydrophobicity and degrading capacity were also investigated.The results showed that the strain was identified as Rhodococcus sp.XY916 and named XY916,with its optimum growth pH of a weak alkaline and tolerable mineralization ranging from 0 to 20 000 mg/L.XY916 could grow well in the solution with phenanthrene content of 120 mg/L.The hydrophobicity of XY916 and the apparent solubility of phenanthrene were improved simultaneously under the effect of low concentration of humic acid,thereby enhancing the contact area between XY916 and phenanthrene,and promoting the degradation of phenanthrene with a removal rate up to 95.3%.