Bio-solubilization of Rock Phosphate Using Acidophilic Bacteria and Effect of Bio-Organic-Phosphate Composite on the Growth of Wheat

Abstract

Acidophilic sulfur and iron oxidizing bacteria, such as Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans, play a crucial role in releasing nutrients into the soil. This study utilized a mixture of these bacteria to solubilize phosphorus from phosphate rock. Acidophilic bacteria were enriched from soil samples taken from the collection pond of a coal heap constructed for biodesulfurization studies. Rock phosphate sample was supplemented with elemental sulfur (S^o) and pyrite (FeS₂) as energy substrates for bioleaching of phosphorus. The effect of different pulp densities of the rock phosphate on biosolubilization of phosphorus elucidated that the pulp density and rock phosphate solubilization are negatively correlated. The mixture of acidophilic microorganisms solubilized 40.76% P₂O₅ at 10 g/L pulp density during 30 days of leaching. A comparative study showed that a two-step process is more effective for the phosphorus leaching from rock phosphate. In pot experiments under net house conditions, the acidophilic bacterial composite increased wheat grain yield by 2% and seed phosphorus content by 3%, while reducing the need for DAP fertilizer by 20%. Treating soil with BOP (a combination of phosphate rock and acidophilic bacteria) proves to be an efficient method for converting frugally soluble phosphorus compounds into readily available forms for plants.

Keywords:

• Acidophilic bacteria
• bio-organic-phosphate composite
• phosphorus bio-solubilization/bioleaching
• rock phosphate
• wheat

Disclosure statement

No potential conflict of interest was reported by the author(s).