Santana, C. A.Piccirillo, C.Pereira, S. I. A.Pullard, R. C.Lima, S. M.Castro, P. M. L.2019-10-112019-10-112019Santana, C. A., Piccirillo, C., A. Pereira, S. I., Pullar, R. C., Lima, S. M., & L. Castro, P. M. (2019). Employment of phosphate solubilising bacteria on fish scales – Turning food waste into an available phosphorus source. Journal of Environmental Chemical Engineering, 7(5), 103403. https://doi.org/10.1016/j.jece.2019.1034032213-2929http://hdl.handle.net/10400.14/28351The increased use of fertilisers is a well-known problem; linked to this, there is an always higher demand for phosphorus (P). Because of this, it is crucial to use P from all possible sources and, if necessary, turn it into a soluble form, available for plants/crops. In this paper we report the use of aerobic phosphate solubilising bacteria (PSB) on the scales of the tilapia (Coptodon rendalli) fish, a waste from the food industry; this is the first time that PSB were employed on fish scales to mediate the available P. The scales were calcined to 700 °C to obtain a nanoscale powdery material (more easily solubilised), made of hydroxyapatite, Ca10(PO4)6(OH)2, a calcium phosphate with very low solubility. Seventeen different PSB strains were tested for their ability to solubilise phosphate (commercial tricalcium phosphate - TCP) and hydroxyapatite from fish scale (FSHA). The best performing bacterial strain (Acidovorax oryzae ZS 1–7) led to a P solubilisation more than 60 times higher than the negative control – at 325 mg/L, almost 40% of the available P was solubilised – one of the highest increased efficiencies reported for PBS. Such solubilisation was linked to a decrease of the pH to more acidic values of about 4. The strain ZS 1–7 showed higher P solubilisation efficiency with fish-derived FSHA than with commercial TCP. This approach showed a promising strategy for the valorisation of residues of the fish industry, turning them into a source of P, to be used for sustainable agriculture.engPhosphorousSolubilisationHydroxyapatitePhosphate solubilising bacteria (PSB)By-products valorisationFish scalesTilapiajournal article10.1016/j.jece.2019.1034032213-343785072528727000492151400117