可降解吡啶的全食副球菌B21-3的筛选鉴定及降解特性

【背景】吡啶作为一种难降解的有机污染物普遍存在于焦化、炼油、皮革和制药等行业的废水中,并对环境造成危害。【目的】治理废水中残留的有机污染物吡啶,筛选高效降解菌。【方法】采用富集培养和选择培养,以石家庄某污水处理厂的活性污泥为材料进行吡啶降解菌的筛选,通过形态特征、生理生化特性、(G+C)mol%测定及16S rRNA基因序列系统发育分析对筛选到的降解菌进行鉴定,并分析其对吡啶的降解特性。【结果】分离筛选到一株能以吡啶为唯一碳源和氮源生长代谢的降解菌B21-3,经鉴定该菌株为全食副球菌(Paracoccuspantotrophus)。菌株B21-3对吡啶的最适降解温度为32°C,最适降解pH为7.0,吡啶浓度为100mg/L时降解率为48.50%±0.02%;通过逐步提高吡啶初始浓度对菌株进行驯化,驯化后菌株可耐受较高浓度吡啶且吡啶降解率显著增加,吡啶浓度为100 mg/L时驯化后菌株B21-3对吡啶的降解率为90.26%±1.70%。驯化后菌株在含吡啶的无机盐平板上传代培养15代后,对吡啶的降解率为89.39%±2.03%。【结论】菌株B21-3具有较强的吡啶降解能力及降解稳定性,该菌株可作为吡啶污染水体生物修复的潜在资源。

Screening, identification and characterization of a pyridine degrading bacterium Paracoccus pantotrophus B21-3

Background] As a refractory organic pollutant, pyridine is commonly found in wastewater from coking, refining, leather and pharmaceutical industries, causing harm to the environment. Objective] To treat pyridine contaminated wastewater, bacteria capable of degrading pyridine were screened. Methods] Pyridine degrading bacteria were isolated from the activated sludge of a wastewater plant in Shijiazhuang by enrichment and selective medium. Bacterium B21-3 was identified by morphological, physiological and biochemical characteristics, (G+C)mol% assay, and 16S rRNA gene phylogenic analysis. The pyridine degradation characteristics were analyzed. Results] A bacterial strain B21-3 that used pyridine as the sole carbon and energy source was isolated and identified as Paracoccus pantotrophus. The optimal pH and temperature for pyridine degradation were 7.0 and 32 °C, respectively. When the initial concentration of pyridine was 100 mg/L, the degradation percentage of pyridine was 48.50%±0.02%. After acclimation by increasing the initial concentration of pyridine, strain B21-3 tolerated higher concentrations of pyridine and the degradation of pyridine increased significantly. Under the pyridine concentration of 100 mg/L, the degradation percentate of pyridine by domesticated strain B21-3 was 90.26%±1.70%. After the acclimatized strain B21-3 was subcultured on mineral salt plates supplemented with pyridine for 15 generations, the degradation percentage of pyridine was 89.39%±2.03%. Conclusion] Strain B21-3 had strong pyridine degradation ability with potential for bioremediation of pyridine contaminated wastewater.