涕灭威降解菌培养条件的优化及降解特性研究

Isolation of aldicarb degrading bacteria and its biodegradation characteristics

分别在山东泰安、聊城、菏泽、枣庄、潍坊长期施用涕灭威的农田采集土样,通过富集培养法筛选出1株降解涕灭威能力较高的细菌ZH-1,经生理生化与分子鉴定,该菌株为鞘氨醇杆菌(Sphingobacteriumsp.)。为使该菌能更好地用于涕灭威残留污染治理,研究其生长和降解的适宜条件。结果表明,适合ZH-1菌株生长和降解的最佳碳源和氮源分别为蔗糖和硝酸钠;振荡(120 r/min)培养时该菌的适宜降解温度为30℃,且在低温时的生长和降解能力优于高温;培养基适宜pH值为7,且偏酸性条件下菌株的降解能力高于偏碱性条件;外加氮源硝酸钠的适宜质量分数为0.3%。在适宜培养条件下,恒温振荡培养5 d后菌株ZH-1对初始质量浓度为12.5 mg/L、25 ng/L、50mg/L、100 mg/L、200 mg/L的涕灭威的降解率分别为51%、58%、69%、50%、35%,对涕灭威的绝对去除量随着涕灭威初始质量浓度的增加而增加。外加氮源质量分数低于0.3%时,菌株的生长量随外加氮源质量分数的增加而增加,因此可在实际应用中加入一定氮源以促进该菌的生长。

This paper is inclined to present our investigation findings on the isolation of aldicarb degrading bacteria and its biodegradation features. For our research purpose, we have collected soil samples from Tai＇ an, Liaocheng, Heze, Zaozhuang, Weifang of Shandong province, respectively, for, in the above said regions, aldicarb has been used for years in different situations. As a strain with higher aldiearb degradation ratio, ZH - 1 has been isolated by the enrichment cultivation. At the same time, our physiological tests indicate that the strain was highly similar with the genus with Sphingobacterium sp. In hoping to make the strain better applicable for the aldicarb residues in governance, we have chosen the strain for further research, along with our study of the optimal conditions for its growth and aldiearb degradation. The results of our investigation also suggest that the sucrose and sodium nitrate should be the best carbon source and nitrogen source for the growth of ZH - 1 and aldiearb degrada- tion. Besides, it has been proved that when the culture was shaken at 120 r/min, the optimal degradation temperature for the strain should be 30 ℃. As compared with the slight alkaline condition, the acid environment tends to be better suitable for aldicarb degradation. Moreover, the removal amount of aldicarb can also be expected to get improved gradually with the increase of the initial mass concentration of aldiearb.