The current interest of scientific study aims at survival mechanisms of the cyanobacteria on the extreme habitats (i.e. building facades and monuments) growing under adverse conditions. The present investigation points towards finding out indigenous which are tolerant of conflicting environmental conditions, such as pH, temperature and calcium carbonate. Three isolates of cyanobacteria Scytonema coactile, Scytonema geitleri and Lyngbya aerugineo–coerulea from a cave, building façade, and temple, Orissa respectively were examined. Tolerance to stress at different pH and temperature were evaluated by quantifying cyanobacteria growth at different time intervals. Tolerance to CaCO₃ was studied by subjecting the isolates to the desired concentration 0.0001 – 1% w/v. Each organism was grown for 15 days at 25°C ± 1°C under continuous light intensity (7.5 W/m²) and then harvested, succeeded by SDS gel-electrophoresis protein analysis. Results revealed that three isolated cyanobacteria species from different sub-aerial habitats responded in a specific manner to different stress conditions and to various concentration of CaCO₃ concerning protein synthesis. A 30 and 38 kDa protein was overproduced by all isolates under pH and temperature stress, whereas for CaCO₃ stress, the protein of 16 and 22 kDa was overproduced by Lyngbya aerugineo–coerulea respectively which concluded that the survival of the isolates under stress conditions depends on specific protein synthesis. Generally, isolates tolerant to different stress may be due to specific protein synthesis for their survival to extreme habitats.