Leng, YirongSoares, Ana2021-06-042021-06-042021-05-25Leng Y, Soares A. (2021) Understanding the mechanisms of biological struvite biomineralisation. Chemosphere, Volume 281, October 2021, Article number 1309860045-6535https://doi.org/10.1016/j.chemosphere.2021.130986http://dspace.lib.cranfield.ac.uk/handle/1826/16734The mechanisms of struvite production through biomineralisation were investigated for five microorganisms (Bacillus pumilus, Brevibacterium antiquum, Myxococcus xanthus, Halobacterium salinarum and Idiomarina loihiensis). After 72–96 h of incubation, the microbial strains tested increased the solution pH from 7.5 to 7.7 to 8.4–8.7, and removed ortho-phosphate (63–71%) and magnesium (94–99%) by biomineralisation. The minerals formed were identified as struvite (i.e. bio-struvite). Within the initial 24 h of incubation, microbial growth rates of 0.16–0.28 1/h were measured, and bio-struvite production was observed when the solution supersaturation index with respect to struvite achieved 0.6–0.8 units. The crystals produced by B. pumilus, H. salinarum and M. xanthus were thin trapezoidal-platy shaped and presented a gap size about 200 μm for intervals between cumulative volume undersize distribution at 50% and 90%. While B. antiquum and I. loihiensis produced crystals of coffin-lid/long-bar shape and a narrow size gap around 100 μm for intervals between cumulative volume percentage of 50% and 90%, indicating homogeneous crystal size distribution. Intracellular supersaturation of struvite phase was achieved within B. antiquum and I. loihiensis cells, corresponding to observation of intracellular vesicle-like structures occupied with electron-dense granules/materials. This study suggests that B. antiquum and I. loihiensis produced bio-struvite through biologically controlled mineralisation. This mechanism is the preferred for recovering nutrients from streams such as wastewater because it allows a link between manipulation of microbial growth conditions and bio-struvite production, even in highly complex streams like wastewater.enAttribution-NonCommercial-NoDerivatives 4.0 InternationalIntracellular clusterPhosphorus recoveryBio-struviteBiomineralisationArticle