Screening and identification of pseudomonas aeruginosa LLJQ-1 and its role in bioleaching of low-grade collophanite

A rod-shaped Gram-negative phosphate solubilizing strain LLJQ-1, isolated from the acidic mine drainages of Yichang Mine, could dissolve about 68.92 % of phosphorous from the collophanite in 10 days. The strain should be identified as Pseudomonas aeruginosa, with its morphological, physiological and biochemical characteristics and the analysis based on its 16S rDNA gene sequence (accession number HM752579.1). The investigation of surface and component changes of bioleached collophanite residues by Infrared spectroscopy (IR) and X-ray diffraction (XRD) and the reverse high performance liquid chromatography (HPLC) analysis of acid components within the collophanite suspension indicated that during the process of bioleaching, insoluble phosphorous Ca5(PO4)3F, Ca10(PO4)5CO3F1.5(OH0.5) and Ca(PO3)2.2H2O within the collophanite could be dissolved to soluble phosphorous CaHPO4 by abundant concentration of bacterial metabolite organic acids (mainly citric acids). It is concluded that bioleaching of collophanite by heterotrophic microorganism Pseudomonas aeruginosa LLJQ-1 is mainly indirect bioleaching of the minerals via organic acids.