green synthesis of nano-sized calcite crystals by ureolytic acremonium egyptiacum iran 5247c associated with grapevine decline

Nano-calcite, or calcium carbonate nanoparticles, is valued for its stability and versatile applications, particularly in agriculture, where it enhances soil quality, regulates ph, improves nutrient delivery, and promotes sustainable crop yields. in this research, nano-calcite was synthesized using acremonium egyptiacum iran 5247c, isolated from grapevine necrotic wood, under sedimentary conditions through fungal urease production. key factors including urea and calcium concentrations, ph, incubation time, and temperature were optimized using a one-factor-at-a-time (ofat) approach, resulting in a maximum yield of 595 mg of calcite per 10 ml of solution. field emission scanning electron microscopy (fe-sem) imaging revealed that the nanocrystals were predominantly spherical, averaging 73.5 ± 8.02 nm in size, with a distribution range of 25 to 125 nm. x-ray diffraction (xrd) and fourier transform infrared-raman (ftir-raman) spectroscopy confirmed a well-defined crystalline calcite structure characterized by carbonate ions. this study reports the first synthesis of nano-calcite using acremonium egyptiacum, with precise control over particle shape and size, an ideal feature for applications in concrete reinforcement, bio-cementation, and agriculture.