Screening Of Ammonia Release Reduction Bacteria And Research On Its Nitrogen Transformation Characteristics

The decomposition of organic compounds containing nitrogen in livestock manure by metabolic activity of microorganisms will release ammonia. The ammonia as the main ingredients of stench, not only pollutes the environment but also wastes nitrogen. In order to reduce ammonia release amount and increase nitrogen content in compost, 28 strains with reducing ammonia release ability isolated from chicken and Myriophyllum plants were separated. Among them, the strains CN1 and YX3 had strong effect on reducing ammonia release. Through further research, the following results are obtained:(1) Strain CN1 is Myriophyllum endophyte, it is determined to 99% homology with the strain of Brevundimonas sp. through VITEK2 identification and constructed the phylogenetic tree, Gram-negative, it was identified as Brevundimonas. VITEK identification system showed that there is 99% probability for strain YX3 which isolated from livestock manure being Acinetobacter baumanii. Combining the morphological characteristics, physiological and biochemical characteristics, strain YX3 is identified as Acinetobacter baumanii. Strains CN1 and YX3 were not produce H2 S.(2) The research shows Na Ac and(NH4)2SO4 is the optimum carbon and nitrogen sources of strain CN1 and YX3. Nitrogen sources have a wide range, which not only could use Inorganic Nitrogen, but also could use Organic Nitrogen. The increase of C/N ratio was beneficial to the growth and metabolism of strain CN1 and YX3. The utilization rate of ammonia nitrogen and ammonia oxidation rate of strain CN1 were respectively 96.20% and 91.11% when the ratio of C/N was 20. There was no significant change in the growth and metabolism. The utilization rate of ammonia nitrogen and ammonia oxidation rate of strain YX3 were 93.41% and 86.40% respectively as the ratio of C/N was 15 which showed that the ammonia oxidizing activity present a decreasing trend. The growth and metabolism ability of strain CN1 was better than strain YX3 at the low C/N ratio. When the ammonia concentration was at 0-145 mg/L, ammonia nitrogen utilization rate and nitrate nitrogen concentration of the strains CN1 and YX3 increased with the addition of ammonia nitrogen concentration. The ammonia oxidation rate was above 85% when the initial ammonia nitrogen concentration was 145 mg/L. The growth and metabolism of strain CN1 and YX3 were greatly inhibited when the initial ammonia nitrogen concentration was more than 580 mg/L. Strain CN1 and YX3 showed good growth activity and high ammonia oxidation in neutral or alkaline environment. Strain CN1 and YX3 had better growth and ammonia oxidation capacity when p H were respectively at 6-9, 7-9. The dissolved oxygen has little effect on strain CN1, but strain YX3 was different, ammonia nitrogen utilization rate increased from 72.89% to 93.63%, ammonia oxidation rate increased from 64.40% to 88.44% when the air volume fraction increased from 40% to 70%. The growth was affected by salinity earlier than the metabolism of strain CN1. The content of the Na Cl range was at 0-4% while the optimum range of ammonia oxidation was 0-3%. The salt tolerance of strain YX3 was weak. The better growth activity and the ammonia oxidation capacity were maintained at the contents of the Na Cl of 2%. Nitrite nitrogen as intermediate product does not have a lot of accumulation(3) In peptone liquid medium, Strain CN1 quickly transformed ammonia nitrogen from the decomposition of peptone into nitrate nitrogen through simultaneous ammonification-ammonia oxidation between 12-48 h. The volatilization of ammonia was reduced during the process. After 48 h the growth rate began to slow down and has downtrend。The ultimate concentration of nitrate nitrogen was up to 135.72 mg/L finally. The ammonia oxidation rate reached 91.41%. Nitrite nitrogen as intermediate product didn’t have too much accumulation. The growth and nitrogen transformation trend of strain YX3 compared with strain CN1 roughly same, but the time of ammonia nitrogen convered to nitrate nitrogen slightly later than the strain CN1. Nitrite nitrogen had a small amount of accumulation at 36 h(0.031 mg/L). Both of the strains had the ability of simultaneous ammonification-ammonia oxidation.(4) Strains CN1 and YX3 only used a small amount of nitrate nitrogen to meet cell growth。Both of the strains had no obvious growth turbidity. The ammonia nitrogen and nitrite nitrogen were not detected during the whole process, which could be preliminarily determined that the strains CN1 and YX3 didn’t have the ability of denitrification.(5) The results from simulation experiment using chicken manure showed that the amount of ammonia nitrogen releases was reduced 90.06% and 84.46% respectively by strain CN1 and YX3 which kept stable effect compared with the control group.