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Nitrosarchaeum haohaiensis sp. Nov. CL1 T : Isolation and Characterisation of a Novel Ammonia‐Oxidising Archaeon From Aquatic Environments

Year: 2025

Type: article

Abstract: ABSTRACT Following a 3.5‐year enrichment cultivation period, a novel ammonia‐oxidising archaeon (AOA), designated strain CL1 T , was isolated from Yangshan Harbour (East China Sea). Strain CL1 T demonstrates a maximum ammonia tolerance of up to 10 mM. Its optimal growth conditions include a pH range of 7–8, a salinity of 2%–3%, and a temperature range of 20°C–25°C. Under these conditions, strain CL1 T achieved a maximum specific growth rate of 0.87 d −1 , with cell yields estimated at 3.92 × 10 6 cells mL −1 μM ammonia −1 . Genomic sequencing revealed that strain CL1 T possesses a genome size of 1.63 megabases with a high completeness of 99.95%. Phylogenetic analysis based on the 16S rRNA gene and whole‐genome data placed strain CL1 T within the genus Nitrosarchaeum . The average nucleotide identity (ANI) between the genome of strain CL1 T and its closest relative was 92.01%, confirming that strain CL1 T represents a novel species within Nitrosarchaeum . Metabolic pathway analysis demonstrated that strain CL1 T encodes key enzymes for ammonia oxidation, including ammonia monooxygenase ( amoA , amoB , amoC ) and copper oxidase, indicating its capacity for ammonia oxidation. Additionally, strain CL1 T likely assimilates ammonia through the GS‐GOGAT and GDH pathways. Consistent with the observation of extracellular vesicles (EVs) in strain CL1 T via electron microscopy, genome annotation identified core genes associated with EVs function, such as vps4 and FtsZ . The isolation of strain CL1 T provides a valuable model system for investigating its ammonia metabolism and exploring its ecological interactions with other AOA, ammonia‐oxidising bacteria (AOB) and nitrite‐oxidising bacteria (NOB), thereby contributing to a deeper understanding of nitrogen cycling mechanisms in aquatic environments.

Source: Environmental Microbiology Reports

DOI: 10.1111/1758-2229.70100