An Aerobic Denitrifier Screened Identification And Denitrification Characteristic

Nitrogen is one of the most important pollutants in the water. It is hazard to people's health and environment. Two forms of nitrogen element in the water are organic nitrogen and inorganic nitrogen. Because of the different nourishment requirement of the nitrifiers and denitrifiers, the process of nitrogen removal is very complex and the application of the biological nitrogen removal is limited. Recently, some new type bacteria by which nitrogen can be effectively removed have been found. This provides a new method to develop the application of the b iological nitrogen removal.In this experiment, a strain of bacteria which has the capacity of aerobic denitrigenation and heterotrophic nitrification was screened .So the strain of bacteria can perform simultaneous nitrification and denitrification.5 strains of aerobic denitrifiers were screened through acclimation and the strain AD3 was found the most high nitrogen removal rate. By 24h culture, the nitrogen removal could reach up to 98%. According to the physiological-biochemical tests and 16S rDNA sequencing analysis, AD3 was identified as Pseudomonas stutzeri. And the unrooted phylogenetic tree of the strain and its neighboring denitrifiers was given. This tree showed that all aerobic denitrifacationors and heterotrophic nitrificationgors had a close genetic relationship.Aerobic denitrifacation of strain AD3 was been disccused. The strain AD3 has a good effect of denitrification under the absolutely aerobic and anaerobic condition. Through the PCR reaction, a specific strip of periplasm nitrate reductase gene sequence was gotten. It can be conclude that the strain AD3 had the capacity of expresses the periplasm nitrate reductase. The factors affecting aerobic denitrification were disccused and the best conditions of aerobic denification were given.The heterotrophic nitrification perfermance of the strain AD3 has been found. When the strain AD3 was cultured in the DM medium, it had higher nitrogen removal. And the relationship of aerobic denitrification and heterotrophic nitrification was discussed. The result showed that aerobic...