The thermophilic proteases were purified from two different Bacillus strains HUTBS62 and HUTBS71. The two strains showed variation in ability to grow at different pH-values and temperatures, pH 5-11 and 28-73oC (HUTBS71) and pH 5-7 and 37-63oC (HUTBS62), respectively. The purified enzyme from the two different strains also showed variation in purification folds and %yields in different steps of purification methods. Ammonium sulfate fractionation was achieved at 75-80% for HUTBS71 and 55-60% concentrations for HUTBS62. The purification fold and yield were 10-fold and 67% for strain HUTBS71, and 6.5-fold and 61% for strain HUTBS62, respectively. Sephadex G-100 purification step achieved 40-fold purification and 16.7% yield from strain HUTBS71, and 32-fold purification and 12% yield of protease from strain HUTBS62. DEAE ion exchange chromatography step achieved 60-fold purification and 1.7% yield for strain HUTBS71, and 53-fold purification and 2% yield for strain HUTBS62. The molecular weight of purified proteases from HUTBS71 and HUTBS62was 49 kDa and 48 kDa, respectively.
