01905naa a2200253 a 450000100080000000500110000800800410001902200140006002400530007410000160012724501660014326000090030930000080031852011000032665300300142665300170145665300260147365300190149965300260151870000140154470000160155870000190157477300580159321325182022-06-10       2021    bl uuuu     u00u1 u    #d  a2589-014X7 ahttps://doi.org/10.1016/j.biteb.2021.1007112DOI1 aLODI, L. A.  aA green K-fertilizer using mechanical activation to improve the solubilization of a low-reactivity potassium mineral by Aspergillus niger.h[electronic resource]  c2021  a1-8  aHere, we investigated process engineering strategies to improve the biological solubilization of K-feldspar, a lowreactivity potassium mineral, aiming to obtain a green K-fertilizer for agricultural applications. The results using submerged cultivation of Aspergillus niger showed that the biological K-solubilization of pristine K-feldspar rock released up to 15.87% (reaching 220 mg L− 1 after 3 days) when using 5% glucose as carbon source and initial pH 4, without a preculture step. Besides medium acidification, the microorganism-mineral physical interaction played a key role in promoting K-solubilization. Furthermore, prior mechanical activation of the K-feldspar led to substantial increases of up to 172% in K release (reaching 326.86 mg L− 1 ), compared to the original mineral, and reduced the K-solubilization cultivation time to only 24 h. The results demonstrated the potential of integrating mechanical activation with biological solubilization to advance on the use of low-solubility potassium minerals as K-fertilizers, thus contributing to a more sustainable agriculture.  aBiological solubilization  aIgneous rock  aMechanical activation  aPotassium rock  aSubmerged cultivation1 aKLAIC, R.1 aRIBEIRO, C.1 aFARINAS, C. S.  tBioresource Technology Reportsgv. 15, e100711, 2021.