Covalent binding of hyper-activated Rhizomucor miehei lipase (RML) on hetero-functionalized siliceous supports
Covalent binding of hyper-activated Rhizomucor miehei lipase (RML) on hetero-functionalized siliceous supports
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DOI：
10.1016/j.ijbiomac.2016.01.076
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发表时间：
2016-05-01
影响因子：
8.2
通讯作者：
Yousefi, Maryam
中科院分区：
文献类型：
--
作者：
Garmroodi, Maryam;Mohammadi, Mehdi;Yousefi, Maryam
疏水载体物理吸附已被证明是提高脂肪酶活性的有效途径。另一方面，共价结合提高了固定化生物催化剂的活性寿命。为了结合吸附和共价结合的优点，报道了将RML固定在新的异功能载体上。为此，通过同时使用两种偶联剂对二氧化硅和二氧化硅介孔纳米颗粒进行化学改性；疏水相互作用用辛基三乙氧基硅烷（OTES），共价键用缩水氧基丙基三甲氧基硅烷（GPTMS）。改变GPTMS/OTES比例可以在支架上添加不同数量的辛基和环氧基。结果表明，将RML固定在辛基功能化载体上产生的比活性几乎是游离酶的1.5-2倍。随着载体上环氧基团的增加，观察到的超活化降低，证实了附着物的共价性质的增强。浸出实验也证实了环氧基对支架的积极作用。考虑固定化制剂的比活性和各载体对RML的解吸率，在GPTMS和OTES存在下，以1:1的比例对载体进行功能化，得到最合适的载体。(C) 2016 Elsevier B.V.版权所有
Physical adsorption onto hydrophobic supports has proven to be an effective way to improve the activity of lipases. Covalent binding, on the other hand, enhances the active lifetime of the immobilized biocatalysts. To combine the benefits of adsorption and covalent binding, immobilization of RML on new hetero-functional supports are reported. For this, chemical modification of silica and silica mesoporous nanoparticles was performed by the simultaneous use of two coupling linkers; Octyltriethoxysilane (OTES) for hydrophobic interaction and glycidoxypropyltrimethoxylsilane (GPTMS) for covalent linkage of RML. Altering the GPTMS/OTES ratio makes possible to have different amount of octyl and epoxy groups on the supports. The results showed that immobilization of RML on octyl-functionalized supports produces specific activity almost 1.5-2 folds greater than the specific activity of the free enzyme. The observed hyper-activation decreased with increasing epoxy groups on the supports confirming the enhancement of covalent nature of the attachment. Leaching experiment was also confirmed positive effect of the presence of epoxy groups on the supports. Regarding the specific activity of the immobilized preparations and desorption percentages of RML from each support, the most suitable carrier obtains from the functionalization of the supports in presence of GPTMS and OTES in the ratio of 1:1. (C) 2016 Elsevier B.V. All rights reserved.