Abstract:Abstract:[Objective] In order to understand the weathering on potassium-bearing mineral by Aspergillus niger, we studied the formation of A. niger-mineral aggregation and polysaccharide in the revolving and fermenting mode and their role in the process of weathering on potassium-bearing mineral. [Methods] We used four different media to study the morphology of A. niger -mineral aggregation; ultraviolet-visible spectrum (UV-Vis), fourier transform infrared spectrum (IR), gas chromatography(GC), scanning electron microscopy(SEM) and energy dispersive spectrometer(EDS) were combined to research the changes of polysaccharide and their significances in the micro-environment forming fungal-mineral aggregation. [Results] A. niger myclia intertwined, adsorbed, chelated and bonded mineral powder to form aggregation by the assistance of polysaccharide and other metabolites. After formation of the aggregation, the concentration and structure of polysaccharide were changed significantly. [Conclusion] The changes of polysaccharide would enhance the adsorption on minerals, chelation on metal ions and adsorption on water molecules, which provided a favorable micro-environment for the fungal using mineral nutrients effectively.