The effect of the high pressure homogenisation on the activity and stability of a commercial neutral protease from Bacillus subtilis

The activity of a commercial neutral protease from Bacillus subtilis after high pressure homogenisation (HPH) was investigated. The enzyme was processed up to 2000 bar, and the residual activity was measured from 20 to 70 °C during refrigerated storage. Moreover, the effect of HPH at high temperatures was evaluated. No improvement in the activities at 55–70 °C were observed after HPH, while an increase of approximately 30% in the 20 °C‐activity was reached after 2000 bar processing. Thus, HPH shifted the optimum temperature from 55 to 20 °C. The high temperature homogenisation caused no changes in 55 °C‐activity, but reduced 20 °C‐activity three times. It suggests that HPH modifies the protease configuration, changing enzyme performance (maximum activity condition), as the efficacy of lock‐and‐key mechanism is strictly dependent on enzyme spatial structure. The changes can be permanent or not, depending on homogenisation pressure, inlet temperature and enzyme storage conditions. Therefore, the HPH is a promising method to change protease characteristics.