The optimization of growth condition of the bacteria producing cold-active proteolytic enzyme from the antarctic region

The growth conditions of bacteria producing cold-active protease isolated from an Antarctic sample were screened using one-factor-at-time (OFAT). Then, crude protease of the strain was extracted during the late logarithmic phase for enzymatic assay. A strain that showed the highest enzyme activity was selected for optimization via response surface method (RSM). The parameters studied were incubation temperature (4 - 36 degrees C), pH media (4 10) and NaCI concentration (0 8%). Based on the OFAT results, all eight strains showed the highest growth rate at 20 C, pH 7 and 4% (w/v) NaCl. The assay showed that the crude enzyme extracted from strain SC8 exhibited significantly higher activity (0.20 U and 0.37 U) than the positive control (0.11 U and 0.31 U) at -20 degrees C and 20 degrees C. RSM suggested that the optimized setting for growth of SC8 were at 20.5 C, pH 6.83 and 2.05% (w/v) of NaCI with the results of the bacterial growth rate value was 3.70 0.06 x 10(6) cells/hr. Optimal growth conditions of SC8 from this study are useful for the large-scale production of cold-active protease in future.