Isolation and characterization of silicate mineral-solubilizing Bacillus globisporus Q12 from the surfaces of weathered feldspar.

A silicate mineral-solubilizing bacterial strain Q12 was isolated from the surfaces of weathered feldspar and identified as Bacillus globisporus Q12 based on the 16S rDNA gene sequence analysis. Three silicate minerals (feldspar, muscovite, and biotite) were used to investigate potassium and silicon mobilization by strain Q12. In liquid cultures, the strain showed better growth on the biotite than on feldspar and muscovite. The biotite was the best potassium source for growth of the strain. Solubilization of potassium and silicon from the silicate minerals by the strain resulted mostly from the action of organic acids. Gluconic acid seemed to be the most active agent for the solubilization of the 3 silicate minerals. Gluconic and acetic acids were likely involved in the solubilization of feldspar. The strain could be acid or alkali and salt tolerant and temperature resistant.