莠去津降解菌的筛选及其降解特性研究

Screening and characterization of atrazine-degrading strains

以从白酒糟醅中分离得到的28株细菌为材料,通过高浓度莠去津固态培养基培养和高效液相色谱检测,筛选得到莠去津降解能力较强的菌株,研究这些菌株的生长动态、莠去津降解动态、共代谢物和环境条件对菌株莠去津降解率的影响。结果表明,10株菌具有降解莠去津的潜能(莠去津降解率为13.3%~41.4%),其中XQB-1、XQB-21、XQB-24和XQB-33的莠去津降解率均大于30%。对这4株菌而言,培养72 h时的生长达到对数生长期,莠去津的降解率达到峰值;共代谢物葡糖糖、柠檬酸钠、蔗糖和丁二酸的添加能促进菌株降解莠去津农药,特别是添加葡萄糖可使菌株XQB-1和XQB-33的莠去津降解率分别提高15.2%和14.3%;环境因素对菌株降解莠去津的能力有明显影响,4菌株对莠去津的最适降解条件为接种量为2%、莠去津质量浓度100~200mg/L、培养基初始pH值为5~6、培养温度为30℃、装液量为75~100 m L/150 m L。

The atrazine-degrading strains were screened using solid culture with high concentration of atrazine and high performance liquid chromatography（HPLC）. The dynamics of growth and atrazine degradation rate were determined,and the effects of co-substrates and environmental condition on degradation rate were also evaluated. The results showed that 10 strains had degradative capability for atrazine with the degradation rate from 13. 3% to 41. 1%,and the maximum degradation rate was obtained with strain XQB-33. Among 10 strains,4 strains（XQB-1,XQB-21,XQB-25,XQB-33）showed high atrazine degradation capacity with degradation rate of 38. 1%,34. 6%,37. 3% and41. 1%,respectively. Furthermore,theses 4 strains reached logarithmic phase and showed the highest atrazine degradation rate after culture in liquid medium for 72 h. After addition of glucose,sodium citrate,sucrose and succinic acid sodium acetate as co-substrates,the degradation rate of 4 strains increased significantly,especially for addition of0. 5% glucose,the degradation rate of XQB-1 and XQB-1 increased by 15. 2% and 14. 3%,respectively. The environmental factors can affect the degradation efficiency. The optimum degradation conditions for these 4 strains were as follows： inoculation amount of 2. 0%,initial atrazine concentration of 100-200 mg/L,initial pH value of 5-6,culture temperature of 30 ℃,and volume of 75-100 m L/150 m L.