氨氧化菌群的筛选及发酵条件的优化

Screening of ammonia-oxidizing bacteria and optimization of fermentation conditions

利用选择性培养基对活性污泥进行连续驯化,筛选出氨氮去除效率较高且稳定的氨氧化菌群。采用聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)技术分析了氨氧化菌群在连续传代过程中菌群的结构差异,并对菌群的发酵培养基及发酵条件分别进行了正交优化和单因子优化。结果表明,该菌群的最佳发酵培养基为每升培养基中含碳酸盐缓冲液15mmol,硫酸铵4.2 mmol,磷酸盐缓冲液12.5 mmol,硫酸亚铁0.9μmol,氯化钙0.4 mmol,硫酸镁1.5 mmol;最佳发酵条件为:接种量为14%,装液量为60 mL/250 mL,温度为35℃。在此条件下,菌群对氨氮的去除效果较优化前提高了155%。

The ammonia-oxidizing bacteria( AOB),with high and stable ammolnia-nitrogen removal efficiency,were continuously enriched from activated sludge using a selective medium. The dynamic changes of commol /Lunity structure were analyzed by polymerase chain reaction-denaturing gradient gel electrophoresis( PCRDGGE) technique. The orthogonal and single-factor experiments were carried out to optimize the culture medium composition and fermentation conditions. Estimated optimum medium was consisted of carbonate buffer,15 mmol;( NH4)2SO4,4.2 mmol; phosphate buffer,12.5 mmol; FeSO4,0.9 μmol; CaCl2,0.4 mmol; MgSO4,1. 5 mmol in1 L medium. The best fermentation conditions were conducted as follows: broth content,60 mL /250 mL; inoculation,14%; incubation temperature,35℃. After optimization,ammonia-nitrogen removal was significantly increased by 155%,comparing with previously developed medium.