固定化脂肪酶对邻苯二甲酸酯污染土壤的修复研究

Remediation of phthalic acid esters contaminated soil by immobilized lipase

土壤中邻苯二甲酸酯(Phthalic acid esters,PAEs)的去除能改善农业生态环境,提高PAEs降解酶的稳定性是提高其去除率及缩短降解半衰期的关键。以玉米秸秆生物炭为固定化载体,以脂肪酶为降解酶,研究了固定化脂肪酶的最佳制备条件及对土壤PAEs的去除。通过对固定化酶活大小的比较,确定了固定化脂肪酶的最佳制备条件:pH为7.5,反应温度为30℃,脂肪酶质量浓度为2 g/L,固定化时间为9 h。在土壤pH为7.5,反应温度为30℃,固定化脂肪酶施加量为2%,土壤中水的质量分数为60%的条件下,固定化脂肪酶对土壤中6种PAEs的去除率为51.38%~84.07%,且6种PAEs的降解均符合一级降解动力学模型;与自然降解相比,固定化脂肪酶处理能使PAEs降解半衰期缩短52.33%~75.86%,表明生物炭固定化脂肪酶可提高土壤PAEs去除率。

The removal of Phthalic acid esters(PAEs)in soil can improve the agricultural ecological environment quality.The stability of PAEs-degrading enzymes is the main factor for improving their removal efficiency and shortening the half-life of degradation.In this paper,the optimal preparation conditions of immobilized lipase using corn straw biochar and its application in the removal of soil PAEs were studied.According to the activity of immobilized enzyme,the optimal preparation condition was obtained:pH 7.5,reaction temperature 30℃,lipase concentration 2 g/L and immobilization time 9 h.Under this condition,together with 2%immobilized lipase addictive,and 60%soil moisture content,the degradation rate of the 6 PAEs in soil ranged from 51.38%to 84.07%,following the first-order degradation kinetic model.Compared with the natural degradation,the degradation half-life of PAEs treated with immobilized lipase was significantly shortened the half-life of PAEs degradation by 52.33%to 75.86%,indicating that this immobilizing approach could improve the degradation rate of PAEs in soil.