Biotransformation of struvite by Aspergillus niger: phosphate release and magnesium biomineralization as glushinskite

Bongkotrat Suyamud, John Ferrier, Laszlo Csetenyi, Duangrat Inthorn, Geoffrey Michael Gadd (Lead / Corresponding author)

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28 Citations (Scopus)
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Struvite (magnesium ammonium phosphate - MgNH4 PO4 ·6H2 O), which can extensively crystallize in wastewater treatments, is a potential source of N and P as fertilizer, as well as a means of P conservation. However, little is known of microbial interactions with struvite which would result in element release. In this work, the geoactive fungus Aspergillus niger was investigated for struvite transformation on solid and in liquid media. A. niger was capable of solubilizing natural (fragments and powder) and synthetic struvite when incorporated into solid medium, with accompanying acidification of the media, and extensive precipitation of magnesium oxalate dihydrate (glushinskite, Mg(C2 O4 ).2H2 O) occurring under growing colonies. In liquid media, A. niger was able to solubilize natural and synthetic struvite releasing mobile phosphate (PO43- ) and magnesium (Mg2+ ), the latter reacting with excreted oxalate resulting in precipitation of magnesium oxalate dihydrate which also accumulated within the mycelial pellets. Struvite was also found to influence the morphology of A. niger mycelial pellets. These findings contribute further understanding of struvite solubilization, element release and secondary oxalate formation, relevant to the biogeochemical cycling of phosphate minerals, and further directions utilizing these mechanisms in environmental biotechnologies such as element biorecovery and biofertilizer applications. This article is protected by copyright. All rights reserved.

Original languageEnglish
Pages (from-to)1588-1602
Number of pages15
JournalEnvironmental Microbiology
Issue number4
Early online date20 Feb 2020
Publication statusPublished - 1 Apr 2020


  • Struvite
  • Aspergillus niger
  • solubilization
  • magnesium oxalate dihydrate
  • glushinskite
  • fungal morphology


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