Nitrogen removal characteristics of novel bacterium Klebsiella sp. TSH15 by assimilatory/dissimilatory nitrate reduction and ammonia assimilation

• Published in: Bioresource technology 2024-02, Vol.394, p.130184-130184, Article 130184
• Main Authors: Ren, Jilong, Tang, Jiajun, Min, Hongping, Tang, Dingding, Jiang, Rui, Liu, Yanchen, Huang, Xia
• Format: Article
• Language: English
• Subjects: Ammonia assimilation gene; Heterotrophic nitrification and aerobic denitrification; Klebsiella sp; Nitrogen metabolic pathway
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2023.130184

[Display omitted] •A novel HNAD strain TSH15 was obtained and identified as Klebsiella sp.•The NH4+-N removal rates of strain TSH15 were 2.99 mg/L/h under optimal conditions.•The whole genome sequence and nitrogen removal metabolic pathway were analyzed.•Ammonia assimilation was the main nitrogen removal path of strain TSH15. A novel strain with heterotrophic nitrification and aerobic denitrification was screened and identified as Klebsiella sp. TSH15 by 16S rRNA. The results demonstrated that the ammonia-N and nitrate-N removal rates were 2.99 mg/L/h and 2.53 mg/L/h under optimal conditions, respectively. The analysis of the whole genome indicated that strain TSH15 contained the key genes involved in assimilatory/dissimilatory nitrate reduction and ammonia assimilation, including nas, nar, nir, nor, glnA, gltB, gdhA, and amt. The relative expression levels of key nitrogen removal genes were further detected by RT-qPCR. The results indicated that the N metabolic pathways of strain TSH15 were the conversion of nitrate or nitrite to ammonia by assimilatory/dissimilatory nitrate reduction (NO3−→NO2−→NH4+) and further conversion of ammonia to glutamate (NH4+-N → Glutamate) by ammonia assimilation. These results indicated that the strain TSH15 had the potential to be applied to practical sewage treatment in the future.