extremely significantp < 0.01
The activities in the pH 4 and pH 10 treatment groups reached 4.9 × 10 4 IU/mL and 2.5 × 10 4 IU/mL, respectively, with extremely significant differences (0.001 < p < 0.01, 0.001 < p < 0.01) compared to the pH 7.4 treatment group.