The foam-induced enzyme denaturation, which often results in a large activity loss, is a common phenomenon in foam fractionation of enzymes. To reduce it effectively, we used a Tween 20-containing antifoaming agent to assist the renaturation of the enzyme molecules adsorbed at the gas-liquid interface during defoaming with pepsin as a model enzyme. We studied the roles of the antifoaming agent and its ingredients in renaturation of the adsorbed pepsin molecules. The results show that during defoaming, Tween 20 in the antifoaming agent was able to assist the adsorbed pepsin molecules to restore their native structures as soon as they were desorbed from the gas-liquid interface. The other ingredients, including polydimethylsiloxane, polyether L61 and aluminum silicate, did not affect the pepsin structure during defoaming. However, they enhanced the Tween 20-assisted renaturation of the adsorbed pepsin molecules by increasing the defoaming efficiency. Furthermore, the separation of the antifoaming agent from pepsin in the foamate had no significant effect on its specific activity. When the addition amount of the antifoaming agent in the foamate was 15.0‰ (v/v), almost all the adsorbed pepsin molecules were reactivated. Therefore, the foam-induced pepsin denaturation was reduced effectively without any changes of the foam fractionation process itself. The results are important to improve the performances of foam fractionation of enzymes.

泡沫诱导的酶变性通常会导致大量的活性损失，这是酶泡沫分离中的常见现象。为了有效地减少它，我们在使用胃蛋白酶作为模型酶消泡的过程中使用了含Tween 20的消泡剂来辅助吸附在气液界面的酶分子的复性。我们研究了消泡剂及其成分在胃蛋白酶分子的复性中的作用。结果表明，在消泡过程中，消泡剂中的Tween 20能够帮助被吸附的胃蛋白酶分子从气液界面解吸后立即恢复其天然结构。其他成分，包括聚二甲基硅氧烷，聚醚L61和硅酸铝，在消泡过程中不影响胃蛋白酶的结构。然而，他们通过提高消泡效率提高了胃蛋白酶分子的吐温20辅助复性。此外，从泡沫塑料中的胃蛋白酶中分离消泡剂对其比活性没有显着影响。当消泡剂在泡沫塑料中的添加量为15.0‰（v / v），几乎所有吸附的胃蛋白酶分子都被重新激活。因此，有效地降低了泡沫诱导的胃蛋白酶变性，而无需改变泡沫分离过程本身。该结果对于改善酶的泡沫分离性能是重要的。