Isolation and identification of an aerobic denitrifying bacteria and its denitrification performance
[Objective]In order to purify nitrogen-rich aquaculture water,an efficient aerobic denitrifying bacteria was screened out.[Method]An aerobic denitrifying bacterium was screened from shrimp pond sediment and water samples by microbial enrichment and separation.The results were compared according to physiological and biochemical characteristics and 16S rDNA sequencing,the strain was identified and the key denitrification genes wereamplified.Nitrogen removal performance of strains under different environmental factors(temperature,carbon source,initial pH)was optimized.Finally,the nitrogen removal abilityof this strain in nitrogen-rich wastewater was investigated.[Result]The aerobic denitrifying bacteria(ZY-F8)isolated from shrimp ponds was initially identified as Stutzerimonas stutzeri.The denitrification enzyme genes nirS and napA were detected in the expression of the strain,indicating that the strain hasdenitrification ability in aerobic environment.In the single factor experiment,it was concluded that the strain had the best denitrification effect under the culture conditions of temperature of 30℃,carbon source of sodium citrate and initial pH of 7.0.The removal rate of nitrate nitrogen reached more than 99%,and the cumulative content of nitrite nitrogen was about 0.002 5 mg/L.[Conclusion]The strain ZY-F8 showed good denitrification performance in the treatment ofaquaculture wastewater,and had a good application prospect in the denitrification process.