Department of Chemistry, Shahreza Branch, Islamic Azad University, P.O. Box 311-86145, Shahreza, Isfahan, Iran.
Department of Chemistry, Shahreza Branch, Islamic Azad University, P.O. Box 311-86145, Shahreza, Isfahan, Iran.
Int J Biol Macromol. 2020 Dec 1;164:1-12. doi: 10.1016/j.ijbiomac.2020.07.103. Epub 2020 Jul 15.
This paper has focused on making suitable carriers for the immobilization of α-amylase from Bacillus subtilis and lipase from Candida rugosa via adsorption on modified Na-sepiolite (SEP). Two modified carriers were prepared by changing the nature of SEP with cetrimonium bromide surfactant at concentrations below the CMC of the surfactant, to produce SEP with monolayer surfactant (MSEP) with hydrophobic properties and above the CMC of the surfactant to produce SEP with bilayer surfactant (BSEP) with hydrophilic properties. The enzymatic activity of immobilized lipase on MSEP (MSEPL) and immobilized α-amylase on BSEP (BSEPA) was successfully tested in the hydrolysis of olive oil and starch. The support modification and immobilization process were characterized by BET, XRD, and SEM techniques. The results demonstrated that the specific activity of MSEPL and BSEPA was 1.74 and 2.28 U/mg, respectively. The remained activity of MSEPL (56.7%) and BSEPA (40.4%) after their incubation at 60 °C for 4 h was much higher than that of free enzymes. The residual activity of MSEPL and BSEPA was 77.4% and 66.7%, after 30 days of storage at 4 °C. The MSEPL and BSEPA also showed good reusability, and their relative activities were 54.0% and 44.2% after ten cycles.
本文致力于通过吸附改性钠基沸石（SEP）来制备合适的载体，以固定枯草芽孢杆菌α-淀粉酶和假丝酵母脂肪酶。两种改性载体是通过用低于表面活性剂 CMC 的十六烷基三甲基溴化铵（CTAB）改变 SEP 的性质来制备的，得到具有疏水性的单层表面活性剂改性 SEP（MSEP），和用高于表面活性剂 CMC 的 CTAB 来制备具有亲水性的双层表面活性剂改性 SEP（BSEP）。通过橄榄油和淀粉的水解成功测试了固定化脂肪酶在 MSEP 上（MSEPL）和固定化α-淀粉酶在 BSEP 上（BSEPA）的酶活力。采用 BET、XRD 和 SEM 技术对载体的改性和固定化过程进行了表征。结果表明，MSEPL 和 BSEPA 的比酶活分别为 1.74 和 2.28 U/mg。在 60°C 孵育 4 小时后，MSEPL（56.7%）和 BSEPA（40.4%）的剩余酶活明显高于游离酶。在 4°C 下储存 30 天后，MSEPL 和 BSEPA 的剩余酶活分别为 77.4%和 66.7%。MSEPL 和 BSEPA 还表现出良好的可重复使用性，重复使用十次后，其相对酶活分别为 54.0%和 44.2%。
