一株咔唑降解菌的鉴定及其降解特性研究

从青海油井口污泥中,分离出一株能高效降解咔唑的细菌B1。采用富集培养法筛选降解菌株,并利用生理生化特征及16S r DNA基因序列分析鉴定菌株种类,利用高效液相色谱法测定培养液中咔唑浓度。研究菌株在不同p H、盐浓度、温度等条件下的降解能力,及外加碳源、氮源和底物浓度对降解效率的影响。经鉴定,菌株B1属于Sphingosinicella sp.。最适温度和p H分别为30℃和7.0,最适条件下菌株B1在72 h内对100mg/L咔唑的降解率可达到98%,同时该菌株在盐浓度小于10 g/L时降解率较高。此外,研究结果显示,添加0.1 g/L的葡萄糖和硫酸铵能明显提高其降解效率,且菌株B1能耐受700 mg/L浓度的咔唑。研究表明,菌株B1具有高效降解咔唑的能力及良好的环境适应性。

Identification and Characterization of a Carbazole-Degrading Bacterial Strain

Carbazole-degrading bacterial strain B1 was isolated from an oil well sludge outlet in Qinghai Province. Degradation strain was screened by enriched culture, and analyzed, identified by physiological properties and 16S rDNA sequence, and the carbazole concentration of the culture was detected by HPLC. The degrading capacities of the strain under different pH, salt concentration and temperature, and the effect of adding carbon, nitrogen sources, and substrate concentration on degradation efficiency were discussed. Through identification, strain B1 was belonged to Sphingosinicella sp.. The 100 mg/L carbazole degradation rate of B1 in 72 h under optimum conditions 30℃ and 7.0 pH could reach 98%, while its degradation rate could be higher when salt concentration was less than 10 g/L. Besides, the degradation rate was significantly improved by adding 0.1 g/L glucose and ammonium sulfate, and the strain B1 could tolerate 700 mg/L carbazole concentration. The results indicated that strain B1 had highly-efficient carbazole degradation ability and favorable environmental adaptability.