Characterization of a novel salt-tolerant strain Sphingopyxis sp. CY-10 capable of heterotrophic nitrification and aerobic denitrification

A novel heterotrophic nitrification and aerobic denitrification (HN-AD) strain CY-10 was isolated and identified as Sphingopyxis sp. When ammonium, nitrate or nitrite was used as the sole nitrogen source (300 mg/L), the maximum nitrogen removal efficiency of strain CY-10 were 100%, 91.1% and 68.5%, respectively. The optimal salinity for ammonia nitrogen removal by strain CY-10 was in the range of 0-5%. At the salinity of 5%, a maximum nitrogen removal rate of 6.25 mg/(Lmiddoth) was realized. Metabonomics data showed that the metabolic levels of sucrose and D-tagatose increased significantly at 5% salinity condition, enabling the strain to regulate osmotic pressure and survive in high-salt environments. Functional genes were successfully amplified by quantitative PCR, and HN-AD pathway of strain CY-10 followed NH4+-N -> NH2OH -> NO2--N -> NO -> N2O -> N-2. These findings show that strain CY-10 has great potential in nitrogen removal treatment of saline wastewater.

Automated summary

A novel heterotrophic nitrification and aerobic denitrification strain CY-10, identified as Sphingopyxis sp., was isolated. The strain exhibited different nitrogen removal efficiencies when ammonium, nitrate, or nitrite were used as the sole nitrogen source. The optimal salinity for ammonia nitrogen removal was found to be 0-5%, and the strain showed increased metabolic levels of sucrose and D-tagatose at 5% salinity condition. The functional genes and pathway of HN-AD were successfully identified, suggesting the potential of strain CY-10 in nitrogen removal treatment of saline wastewater.