A green technique of silica nanoparticles (SiO2-NPs) formation by using a thermophilic bacterium (BKH1) as biological template is demonstrated here. SiO2-NPs are synthesized from inorganic (magnesium tri-silicate), and organic (tetraethyl orthosilicate) precursor with the help of BKH1 bacteria. BKH1 derived SiO2-NPs are subjected to Atomic Force Microscopy, Transmission Electron Microscopy, and Field Emission Scanning Electron Microscopy equipped with Energy Dispersive X-ray Analyzer to establish nanoparticle morphology. In addition, Infrared Spectroscopy reveals the presence of chemical and functional groups in SiO2-NPs samples and X-ray diffraction, the amorphous nature. The Zeta potential (ζ) reveals substantial stability of bacteria derived SiO2-NPs in the aqueous environment. Presence of two intense luminescence peaks in the UV and visible regions merits the bacteria derived SiO2-NPs for use as an optical probe in biomedical applications. This novel mode of bacteria derived SiO2-NPs formation is eco-friendly and ambient temperature synthesis approach. It avoids the complex protocol of multi-steps synthesis of silica nanoparticles, hence likely to be cost-effective. In-depth translation research is suggested for the synthesis of silica nanoparticles in large quantities using thermophilic BKH1 template.