Growth of Bacillus amyloliquefaciens as influence by Si nutrition

The aim of study was to determine the influence of soluble and solid forms of Si on the growth of B. amyloliquefaciens. The experiment was conducted at two regimes: under sterile conditions (without B. amyloliquefaciens) and infected conditions (with B. amyloliquefaciens). New formed silica gel, diatomite and monosilicic acid at 1 mM Si and 2 mM Si were used as source of Si. The concentration of monosilicic acid in the solution was measured on second and tenth days of experiment. The total carbon in the solution before and after centrifugation was determined on day 10 of the experiment. The experiment has demonstrated a significant positive effect (by 4.7-41.2%) on B. amyloliquefaciens growth in water system. The presence of B. amyloliquefaciens in Si-rich solution reduced the concentration of monosilicic acid in the solution up to 16.2%. About 13.5-30.7% of B. amyloliquefaciens can be attached to the Si-rich surface without formation of cell clusters. Si can be classified as a beneficial nutrient for B. amyloliquefaciens. The tested strain of Bacillus can form channels in silica gel. The presence of monosilicic acid resulted in the formation of an aligned positioning of cells in water-based solution. This study is the first to demonstrate the direct influence of active Si forms on bacteria growth. The research showed that monosilicic acid or Si-rich solid substances with high solubility on Si can be recommended to increase B. amyloliquefaciens growth in soil, water or reactors.