Biological Nitrogen Removal Database

A manually curated data resource for microbial nitrogen removal


Nitrogen is an essential element in water body, sediment and soil matrix. Occurring mainly in dissolved forms such as ammonium (NH4+), ammonia (NH3), nitrate (NO3-), nitrite (NO2-), and as organic molecules such as amino acids. Nitrogen in adequate concentration levels is required for growth and metabolism of organisms and plants. However, problems arise when high levels of nitrogen are discharged into the environment resulting in algae blooms, contributing to the eutrophication of water bodies, and decrease in the dissolved oxygen concentration. In humans’ excessive intake of nitrate and nitrite can cause methemoglobinemia in infants and the compounds are known as carcinogenic nitrosamines. Nitrogenous contaminants can be removed by a variety of physiochemical and biological methods, with the latter being widely applied in the removal of ammonium because it is effective, inexpensive, less chemical requirements, and energy consumed.

Microbial nitrogen removal database (BNRdb) is a novel manually curated integrative resource concerned with biological nitrogen removal (BNR), serving as a user-friendly access point for the utilization and querying of a catalog of experimentally validated genetic and biochemical information of BNR capable microorganisms. BNR associated genomic datasets are essential for improving bioreactor system stability, nitrogen removal efficiencies, and setting up of optimal biotechnological and environment parameters in nitrogen removal. The database incorporates a set of utilities, enabling interactive data browsing, sequence homology searches, multiple sequence alignments, and phylogeny exploration. For instance, based on the information obtained from the BNRdb, it facilitates the addition of an appropriate archaeon to biological wastewater treatment systems resulting in effective nitrogen removal processes. BNRdb is a reference guide facilitating gene mining and the creation of genetic toolboxes for predictive microbial ecological studies of BNR capable microbes. Studying functional microbial guilds helps researchers understand microbial ecology and encourage the development of effective biodegradation technologies that ensure high performance in environmental remediation.

Organism included

The database contains data on microbial isolates that have been described to possess nitrogen removal capabilities.


This is the first release of BNRdb and it is in its infancy, and thus is incomplete. The database will be periodically updated to accommodate new literature entries that are continuously updated on the NCBI and other public repositories. Manual curation of data will be carried out to detect and remove multiple data entries when conflicting datasets are detected. When making use of the datasets contained in BNRdb, researchers are urged to verify the authenticity and validity of the datasets. Any queries or data issues concerning the BNRdb can be reported via the contact feature incorporated into the BNRdb. And the administrator will respond to their queries.

Data sources

Where appropriate sources from which the data included in BNRdb was extracted were cited. For example, citing the relevant sources such as NCBI (e.g GenBank, GenPept, FASTA formats) and relevant literature sources from which valid data was extracted were also cited for each data entry.