Globally, cement is the most often used building material, but its traditional manufacture comes with significant environmental impacts along with restrictions on cost and quality. Calcium carbonate (CaCO₃) is a commonly used substance in this context. To overcome these obstacles, biological building materials are becoming sustainable technology. Recently, the production of CaCO₃ by bacteria has garnered attention due to its environmentally friendly and health-conscious approach. In this study, Bacillus sp. 8WNM was isolated from Wadi El Natrun lake, Egypt and evaluated for its ability to precipitate CaCO₃ through biomineralization using different calcium compounds, including calcium nitrate (Ca(NO₃)₂), calcium acetate (Ca(CH₃COO)₂), and calcium chloride (CaCl₂). The precipitated CaCO₃ was characterized using Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) analyses. Among the tested sources, calcium acetate was the most effective, yielding the highest amount of precipitate. XRD analysis confirmed that the obtained CaCO₃ exhibited a single-phase structure, while FTIR analysis identified peaks corresponding to CaCO₃. The precipitated particles were mainly cubic, consisting of Ca (15.38±1.34%), C (23.21±1.08%), and O (61.41±3.84%). Optimal conditions for CaCO₃ precipitation were achieved with a calcium source concentration of 2.5 g/L, an inoculum size of 1.5 mL, and an incubation period of 8 days, resulting in a production yield of 0.236 g/100 mL. The promising results obtained by precipitating CaCO₃ using Bacillus sp. 8WNM recommend its usage in the bioconstruction materials production that are both financially sustainable and socially and environmentally beneficial.