[Objective] To study the effect of K release and weathering of K-bearing minerals by Penicillium oxalicum. [Methods] The element compositions in the liquid phase and on the mineral surface were determined by Inductively Coupled Plasma, X-ray Energy Dispersive Spectrometer and X-ray Photoelectron Spectroscopy. The crystal structure was analyzed by X-ray diffraction after the mineral was incubated with P. oxalicum. The biofilm formed onto K-bearing minerals was determined by Confocal Laser Scanning Microscope. The effect of carbon source and nitrogen source on K mobilization by P. oxalicum was also studied. [Results] Biotite showed less resistance to fungal bioweathering, compared with K-feldspar and muscovite, and P. oxalicum formed network structure biofilm where probably the organic acid was concentrated. Different carbon and nitrogen source could be used by P. oxalicum. [Conclusion] P. oxalicum can accelerate the bioweathering and K release of different K-bearing minerals and has application potential in compost and biofertilizer.
