Bio-Weathering of Feldspar and Talc by Silicate- Solubilizing Bacteria Isolate from Green Fodder Cultivated Sandy Soil

Abstract

Silicon and potassium are important nutrients to plant growth and development. However, their mineral resources in soil matrix are poorly soluble. The current study aims to increase the concentration of these nutrients in rhizosphere soil to meet the plant need. To achieve this goal, two strains of silicate solubilizing bacteria (SSB) were isolated from rhizosphere of green fodder grown on sandy soil and identified as Bacillus cereus AUMC-B 477 with accession number SUB12524150 L1 OQ220474 and Enterobacter kobei AUMC-B 478 with accession number SUB12524150 L2 OQ220475. Their efficiency to release silicon and potassium from silicate, rich minerals viz, feldspar and talc were evaluated. The SEM images indicated degradation of feldspar and talc surfaces by both strains. Release of silicon and potassium was obviously enhanced in the inoculated culture media compared to the noninoculated ones. This was correlated with the decrease in culture pH due to secretion of organic acids. Such acidification process may figure out that acidolysis process might be one of the possible breaking down of feldspar and talc by either Bacillus cereus AUMC-B 477 or Enterobacter kobei AUMC-B 478. The findings revealed that Enterobacter kobei AUMC-B 478 applied with K-feldspar was more efficient for releasing more silicon and potassium into the culture media. Further study in pot experiments is recommended using Enterobacter kobei AUMC-B 478 to insist its capability to overcome soil deficiency in silicon and potassium.