Bacterial communities associated with the cycling of non-starch polysaccharides and phytate in aquaponics systems

Daniel Menezes-Blackburn*, Nahad Al-Mahrouqi, Buthaina Al-Siyabi, Adhari Al-Kalbani, Ralf Greiner, Sergey Dobretsov

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Aquaponics are efficient systems that associate aquatic organisms’ production and plants by recirculating water and nutrients between aquaculture and hydroponic tanks. In this study, we characterised the bacterial communities in the freshwater aquaponics system that can mineralise polysaccharides and phytate by producing carbohydrate-degrading enzymes and phytases, by 16S rRNA gene sequencing and in vitro culture techniques. Around 20% of the operational taxonomic units (zOTUs) identified were previously reported to carry fibre-degrading enzyme putative genes, namely β-glucanase (1%), xylanase (5%), or cellulases (17%). Ten % of the zOTUs were previously reported to carry putative genes of phytases with different catalytic mechanisms, namely β-propeller (6%), histidine acid phytases (3%), and protein tyrosine phytase (<1%). Thirty-eight morphologically different bacteria were isolated from biofilms accumulated in fish and plant compartments, and identified to belong to the Bacilli class. Among these, 7 could produce xylanase, 8 produced β-glucanase, 14 produced cellulase, and 11 isolates could secrete amylases. In addition, Staphylococcus sp. and Rossellomorea sp. could produce consistent extracellular phytate-degrading activity. The PCR amplification of β-propeller genes both in environmental samples and in the isolates obtained showed that this is the most ecologically relevant phytase type in the aquaponics systems used. In summary, the aquaponics system is abundant with bacteria carrying enzymes responsible for plant-nutrient mineralisation.

Original languageEnglish
Article number631
Issue number12
Publication statusPublished - Dec 2021


  • Aquaponics
  • Bacterial communities
  • Carbohydrases
  • Metabarcoding
  • Phytases

ASJC Scopus subject areas

  • Ecology
  • Ecological Modelling
  • Agricultural and Biological Sciences (miscellaneous)
  • Nature and Landscape Conservation


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