Application Study Of AmoA Gene In Population And Quantitative Analysis For Ammonia-Oxidizing Bacteria

Biodenitrify is a universal method in mordern wastewater treatment. Nitrification performed by nitrifying bacteria is a key process in removing high ammonia-nitrogen concentration in wastewater. Chemolithoautotrophic nitrifying bacteria have many unfavorable physiological characteristics, which made the effect of denitrify very unstable in the wastewater treatment plants. To find out the running situation of these denitrify systems, we analyzed the activated sludge from two different wastewater treatment systems, made the rapid quantitative analysis of ammonia-oxidizing bacteria by using MPN-PCR method, and calculated the nitrifying velocity from the change of ammonia-nitrogen concentration by using spectrophotometer. The result showed that the amount and activity of nitrifying bacteria in the biodenitrify system are important standards to judge the effect of denitrify in that system.Ammonia-oxidizing bacteria is a key group of nitrifying bacteria, and its population is variable with the different environment. In order to analyze the composition of ammonia-oxidizing communities in the wastewater treatment system, we selected and designed a pair of primers special for the amoA gene and used PCR to amplify the specific DNA fragment from the total bacterial DNA extracted from the wastewater. After TA cloning and DNA sequencing, different sequences were compared to the available databases by using the BLAST network service. We found that there were a quantity of Nitrosomonas genus in the wastewater treatment system and the mostly of which is Nitrosomonas europaea. The result suggested that Nitrosomonas genus probably played a predominant role in the ammonia oxidation in the system. Analyzing the phylogenetic development between different species in Nitrosomonas by Clustal and PHYLIP software, we set up the phylogenetic tree often species according to amoA gene.