一株菲降解菌筛选鉴定及降解性能研究

Isolation,identification and degradation conditions of phenanthrene-degrading bacterium

采用菲降解菌筛选方法从大庆油田受石油污染土壤中分离得到1株对菲具有较好降解效果的菌株，命名为H3。通过形态观察、生理生化鉴定及16SrDNA序列分析发现，该株菌为寡养单胞菌属Stenotrophomonas sp．，研究其降解条件。结果表明，在30℃，接种量10％条件下，菲菌株对初始质量浓度为100mg·L^-1在12d内降解率高达98．6％。研究发现，H3菌对高质量浓度菲有较好的耐受性，其最高耐受质量浓度可达1000mg·L^-1，且菌H3具有较广泛pH耐受性，其可适应pH范围是6．5-9．0。

A set of high efficiency and convenient method was established to isolate phenanthrene-degrading strain, by which, one strain with high and steady phenanthrene-degrading activity was isolated from soil contaminated by heavy oil from Daqing Oilfield. The strain H3 was identified according to its morphological, physiological, biochemical, and 16S rDNA sequence characteristics. The results indicated the phenanthrene-degrading bacterium belonged to the Stenotrophomonas sp.. Moreover, the biochemical degradation of phenanthrene was further studied. Under the optimumconditions of 30 ℃, inoculum concentration （10%） and phenanthrene mass concentration of 100 mg· L^-1, the degradation rate of phenanthrene reached 98.6% in 12 d. The strain has a good tolerance to high concentrations of the phenanthrene and a large range of pH value. Its maximum tolerated concentration can reach 1 000 mg· L^-1, and the optimal pH value is 6.5-9.0.