Nitrate removal in aquariums by immobilized Pseudomonas

Y. Tal, A. Nussinovitch, J. Van Rijn*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


Biological denitrification of nitrate to nitrogen gas was examined in a freshwater and a marine aquarium. Nitrate removal in the aquarium water was accomplished with denitrifiers immobilized in a freeze-dried, alginate-starch matrix. Starch served as a bacterial carbon source and cellular matrix-strengthening filler. Freeze-dried beads were placed in canisters through which nitrate-rich aquarium water was recirculated. The freshwater aquarium (100 L) contained goldfish (Carassius auratus) at a total biomass of 390 g, whereas cichlids (Oreochromis mossambicus) were kept at a similar stocking density in the marine aquarium. Denitrification resulted in low ambient nitrate concentrations in both aquariums. The specific nitrate removal rate of the freshwater beads was significantly higher (50 μg of NO3-N/bead/day) than that of seawater beads (5 μg of NO3-N/bead/day). Differences in ambient nitrate concentrations between both aquariums and diffusion limitation of nitrate to the active denitrification sites within the beads might explain these observed differences.

Original languageAmerican English
Pages (from-to)1019-1021
Number of pages3
JournalBiotechnology Progress
Issue number3
StatePublished - May 2003


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