Isolation And Identification Of Heterotrophic Sulfur-oxidizing Bacteria And Research Of Hydrogen Sulfide-released In Chicken Manure

With the rapid development of large-scale livestock breeding industry, the emissions of livestock and poultry wastes continue to increase, sulfur-containing organic matter of emissions under the action of microorganisms can release a large amount of hydrogen sulfide gas, which serious damage the health of livestock and poultry and pollute the environment, has become urgent environmental problems to solve. The purpose of this study is to reduce the amount of hydrogen sulfide emission. 33 strains were isolated from livestock feces and aquatic plants, two strains bacteria with high hydrogen sulfide- released and named CN2 and JS3 were selected to do a lot of experiments, the main results are as follows:（1）Strain CN2 is a gram negative pole, edge neatly, surface smooth, circle and milky white bacteria, which was screened from the feces of livestock and poultry. VITEK 2 identification results showed that the possibility with Pseudomonas sp was 91%, phylogenetic trees showed that the strain CN2 had the highest homology with Pseudomonas sp. Strain JS3 is a gram negative pole, edge saw tooth shape, surface smooth, thick and milky white bacteria, which was screened from aquatic plant potamogeton crispus, VITEK 2 identification did not find bacteria of high similarity with the strain JS3, phylogenetic tree showed that the strain JS3 had the highest homology with Aeromonas salmonicida.（2）Priority utilization order of carbon source of sulfur oxidation by strain CN2 was sodium citrate>glucose>sodium acetate, nitrogen source was ammonium nitrate> ammonium chloride; Priority utilization order of carbon source of sulfur oxidation by strain JS3 was glucose>sodium citrate > sodium acetate, nitrogen source was ammonium chloride > ammonium nitrate. The growth and sulfur oxidation trend by strain CN2 and JS3 were first increased and then decreased with the carbon nitrogen ratio increased from 5:1 to 20:1, the best carbon nitrogen ratio was 15:1, at this time, 73.39% of thiosulfate was converted to sulfate by strain CN2, 76.25% of thiosulfate was converted to sulfate by strain JS3. Sulfur oxidation ability were first increased and then decreased by two strains with p H increased from 4.05 to 10.05, when p H was 7.05, the OD600 was 1.827 by strain CN2, the accumulation of sulfate was the highest, which was up to 4.33 g/L. When p H was increased to 10.05, there was still 1.38 g/L sulfate accumulation; when p H was 9.05, the OD600 was 1.891 by strain JS3, the accumulation of sulfate was the highest, which was up to 4.37 g/L, When p H was increased to 10.05, there was still 3.89 g/L sulfate accumulation. Significant effect on the strain CN2 and strain JS3 was produced when the amount of sodium chloride reached 3% and 4%, respectively, which illustrated that the strain CN2 and strain JS3 were all have a certain salt resistance and strain JS3 was higher than strain CN2. There was no significant effect on the growth of strain CN2 and JS3 when the initial concentration of thiosulfate increased from 702 mg/L to 5620 mg/L, sulfur oxidation trend was first increased and then decreased, the optimal initial concentration of thiosulfate was 2810 mg/L, 81.43% of thiosulfate was converted to sulfate by strain CN2, 83.22% of thiosulfate was converted to sulfate by strain JS3. There was no obvious effect on the growth and sulfur oxidation and ammonium oxidation by strain CN2 when liquid volume of 250 m L triangular bottle was reduced from 150 m L to 25 m L which means the content of dissolved oxygen was increased, sulfur oxidation trend of strain JS3 was first increased and then decreased, when the liquid volume was 75 m L, 80.72 % of thiosulfate was converted to sulfate. When the amount of nitrogen source was changed, with sulfur nitrogen ratio increasing from 20:1 to 5:1, the conversion rate of thiosulfate and ammonia nitrogen were increased, when sulfur nitrogen ratio was 10:1, the conversion rate of thiosulfate and ammonia nitrogen were the highest, which was 80.72% and 87.36%, respectively, the conversion rate were all decreased with the content of nitrogen continued to increase; When the amount of sulfur source was changed, with sulfur nitrogen ratio increasing from 5:1 to 20:1, the conversion rate of thiosulfate was increased with the increase content of sulfur, when sulfur nitrogen ratio was 10:1, 68.12% of thiosulfate was converted to sulfate, conversion rate was decreased with the continued increase of sulfur content, but there was no obvious effect on the ammonia oxidation ability with the change of sulfur nitrogen ratio, the utilization rate of ammonia nitrogen was above 80%.（3）In the chicken manure laboratory simulated experiment, the strain CN2 can reduce 81.36%release of H₂S and reduce 88.79%release of NH3 compared with the control group, the strain JS3 can reduce 77.45% release of H₂S compared with the control group. The above results showed that strain CN2 could reduce the volatilization of H₂S and NH3, strain JS3 could reduce the volatilization of H₂S, which could provide good environment for farms.