Abstract The esterase SulE is known to be an important and primary enzyme for the degradation of many sulfonylurea herbicides such as tribenuron-methyl, metsulfuron-methyl, and chlorimuron-ethyl. The disadvantages of applying free enzyme include poor stability and rapid deactivation in the natural environment, but these problems can be mitigated by using immobilized enzymes. In this study, cross-linked gelatin/chitosan (GLT/CTS) was selected as the enzyme immobilization carrier because its SulE activity recovery was higher than those of γ-polyglutamate/gelatin (γ-PGA/GLT) and γ-polyglutamate/chitosan (γ-PGA/CTS). The immobilization conditions were further optimized, and the effects of pH and temperature on GLT/CTS-SulE and free SulE activities to degrade tribenuron-methyl and metsulfuron-methyl were investigated. A microcosm experiment was conducted to assess the effectiveness of GLT/CTS-SulE in remediating soils polluted with tribenuron-methyl and metsulfuron-methyl. The results showed that, compared with free SulE, GLT/CTS-SulE displayed better pH and temperature adaptabilities and higher degradation efficiencies for both herbicides in soil, especially tribenuron-methyl. The results indicate that this is an excellent method to immobilize SulE for enhanced remediation of soils polluted with tribenuron-methyl or metsulfuron-methyl in situ.

中文翻译：

---

酯酶SulE在交联明胶/壳聚糖中的固定化及其在甲基苯磺隆和甲基嘧磺隆污染土壤修复中的应用

摘要 酯酶 SulE 是降解许多磺酰脲类除草剂如苯磺隆、甲基嘧磺隆和乙基氯嘧磺隆的重要酶。应用游离酶的缺点包括在自然环境中稳定性差和失活快，但这些问题可以通过使用固定化酶来缓解。本研究选择交联明胶/壳聚糖（GLT/CTS）作为酶固定化载体，因为其SulE活性恢复率高于γ-聚谷氨酸/明胶（γ-PGA/GLT）和γ-聚谷氨酸/壳聚糖(γ-PGA/CTS)。进一步优化了固定化条件，研究了pH和温度对GLT/CTS-SulE和游离SulE降解甲基苯磺隆和甲基嘧磺隆的活性的影响。进行了微观实验以评估 GLT/CTS-SulE 在修复受甲基苯磺隆和甲基嘧磺隆污染的土壤中的有效性。结果表明，与游离 SulE 相比，GLT/CTS-SulE 对土壤中两种除草剂，尤其是苯磺隆，表现出更好的 pH 和温度适应性以及更高的降解效率。结果表明，这是一种极好的固定 SulE 的方法，用于加强原位修复受甲基苯磺隆或甲基嘧磺隆污染的土壤。尤其是苯脲甲基。结果表明，这是一种极好的固定 SulE 的方法，用于加强原位修复受甲基苯磺隆或甲基嘧磺隆污染的土壤。特别是苯脲甲基。结果表明，这是一种极好的固定 SulE 的方法，用于加强原位修复受甲基苯磺隆或甲基嘧磺隆污染的土壤。