Effect of ionic liquids, organic solvents and supercritical CO2 pretreatment on the conformation and catalytic properties of Candida rugosa lipase
Effect of ionic liquids, organic solvents and supercritical CO2 pretreatment on the conformation and catalytic properties of Candida rugosa lipase
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离子液体、有机溶剂和超临界CO2预处理对假丝酵母脂肪酶构象和催化性能的影响
DOI：
10.1016/j.molcatb.2013.01.028
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发表时间：
2013-06-01
影响因子：
--
通讯作者：
Yan, Yunjun
中科院分区：
文献类型：
--
作者：
Liu, Yun;Chen, Dawei;Yan, Yunjun
本工作的目的是评估17种离子液体(ILS)、5种有机溶剂和超临界二氧化碳(SC-CO2)对皱纹假丝酵母脂肪酶(CRL)的结构和活性的影响。结果表明，离子液体的阴离子选择对CRL酯化活性的影响一般比阳离子选择大得多，经ILS处理的CRL具有很强的水混溶性能，其酯化活性很低。IL[Hmim][PF6]处理的CRL活性最高，为45078.0 U/g蛋白。此外，还考察了五种常规有机溶剂处理后的CRL活性，当logP小于2.0时，CRL活性随有机溶剂的logP降低而增大。在40℃、压力分别为6 Mpa和15 Mpa的条件下，用亚临界和超临界CO2处理20分钟后，CRL活性分别是未处理的1.2倍和1.3倍。FT-IR进一步分析表明，离子液体、有机溶剂和超临界CO_2处理后的CRL活性较高，可能是由于CRL二级结构发生变化所致。综上所述，本工作的结果将有助于我们在CRL生物催化和生物转化反应中选择合适的反应介质。(C)2013爱思唯尔B.V.保留所有权利。
The objective of this work is to assess the structure and activity of Candida rugosa lipase (CRL) pretreated with seventeen ionic liquids (ILs), five organic solvents and super-critical carbon dioxide (SC-CO2). The results revealed that anion selection of ILs showed generally much greater effects on CRL esterification activity than cation choice, and CRL pretreated by ILs with strong water miscible properties showed very low esterification activity. The highest CRL activity treated with ILs [Hmim][PF6] was obtained with the value of 45078.0 U/g-protein. Furthermore, the CRL activities pretreated with five conventional organic solvents were also examined and the values increased with the log P decrease of organic solvents when log P was lower than 2.0. Finally, the CRL activities were respectively 1.2- and 1.3-fold higher over the untreated ones after pretreatment with sub- and super-critical CO2 under the pressures of 6 MPa and 15 MPa at 40 degrees C for 20 min. Further analyses via FT-IR demonstrated that the high activity of CRL pretreated with ILs, organic solvents and SC-CO2 was probably caused by the changes of CRL secondary structure. In conclusion, the results in this work will be helpful for us to choose the suitable reaction medium in CRL biocatalysis and biotransformation reactions. (C) 2013 Elsevier B.V. All rights reserved.