The Breeding Of Denitrification Bacteria And Their Action On Nitrogen Transformation In The Aquaculture Water

Aerobic denitrifying bacteria are concerned by researchers all over the world since they are found. It can overcome the defects of traditional anoxic denitrification process. It can carry on the denitrification under aerobic condition, having a strongly potential application. In the paper, We use the denitrifying bacteria breeding in the lab to improve their denitrifying ability by UV mutagenesis. Then we use it to study the change of nitrogen in aquaculture water. The series data, which is the change of different types of nitrogen concentration with the timing passing, is fitted. We discuss the change of N elements under the different water conditions.Strain 6#, which breed in the lab before, is treated by UV. Strain H2 is obstained after the first and the second screening of 6#, The aerobic denitrification performance is studied. Results show that denitrification ability of strain H2 improves under the same experimental conditions. Compared with original strain, the ability of H2 to remove nitrate is 68.66%, more than original strain of 59.86%. Genetic stability of H2 is good after many times of mutant screening, activation and cultivation process. In the duchenne tubular experiment, strain H2 can produce much gas of 2.5 mL than original strain of 2 mL. We can get the conclusion that H2 has better nitrification and denitrification compared with the original strain 6#.In experiment of imitation aquaculture water, we choose four simulation environments, which are blank water, aquatic plants+bacteria, bacteria only and aquatic plants only, to explore the purifying ability of bacteria H2 water and the impact of aquatic plants. The best treatment ability is aquatic with bacteria, and bacteria, aquatic, blank water, respectively. It proves that H2 has the ability to remove ammonia, nitrate, nitrite, COD, especially to nitrite. H2 is good for water purification, also do aquatic plants. Both Bacteria and aquatic plants can improve water quality and enhance the growth performance offish.The data of change of nitrogen concentration in imitation aquaculture water with the time passing is analyzed by math tool. The equation can reflect transformation rule of nitrogen in aquatic water. We can get the conclusion that H2 and aquatic plants have a obvious regutetion of nitrogen removal from the model equations.Studies show that using UV mutagenesis method can effectively improves the denitrification and purification ability of denitrifying bacteria. It is remarkable of denitrification in aquaculture water.