Fig. 4

Enzymatic activity of TrepCel3 and TrepCel4 in different salt solutions. a Effect of NaCl on the activities of TrepCel3 and TrepCel4; b Effect of NaCl on the stabilities of TrepCel3 and TrepCel4; c The enzyme activity of TrepCel3 in artificial seawater compared with that in 3 mmol/L NaCl and the salt-free condition. The activity was calculated as relative (%) to the enzyme activity in the salt-free at 40 °C; d The enzyme activity of TrepCel4 in artificial seawater compared with that in 5 mmol/L NaCl and the salt-free condition. The activity was calculated as relative (%) to the enzyme activity in the salt-free at 50 °C. All the data values represent the means ± SD