Biosolubilization of rock phosphate by Pleurotus ostreatus with brewery sludge and its effect on the growth of maize (Zea mays L.)

Abstract

Rock Phosphate (RP) is a natural phosphorus source which can be an alternative to chemical fertilizers; but unfortunately, we lack technologies to make it applicable in alkaline soils. Therefore the aim of this work was to study the effects of phosphorous solubilizing fungus Pleurotus ostreatus on rock phosphate solubilization and its effect on growth of Zea mays L. incorporated with brewery sludge. The activity of the selected strain indicates the formation of the halo zone supplemented with rock phosphate. The maximum concentration of soluble phosphorus (P) was found at the 9th day of incubation in Pikovskaya’s broth containing rock phosphate as P source. The inoculation of P. ostreatus with RP and brewery sludge significantly increased the root length (49%), shoot length (27%), root fresh weight (20%), root dry weight (46%), shoot fresh weight (89%), shoot dry weight (87%), chlorophyll content (79%) and nutrient accumulation, i.e., P (2.13), K (4.48), Ca (134.21), Mg (38.09), Cu (1.70), Mn (5.15), Zn (12.08), S (78.25) times greater than control in Zea mays L. The phosphatic residues after microbial solubilization showed structural and elemental changes confirmed by SEM and FE-SEM attached with energy-dispersive X-ray. The XRD and FTIR pattern shows that the mineral constituent of the treated sample signifies the proper P solubilization. Though few reports are available on P. ostreatus but biosolubilization with rock phosphate in the presence of brewery sludge is not yet reported. Overall, these findings suggest a possible application of the abundant waste materials on the sustainable growth of the plants.