Isolation, Characterization, and Catalytic Properties of a Novel Lipase Which Is Activated in Ionic Liquids and Organic Solvents
Isolation, Characterization, and Catalytic Properties of a Novel Lipase Which Is Activated in Ionic Liquids and Organic Solvents
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DOI：
10.1007/s12010-011-9296-x
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发表时间：
2011-10-01
影响因子：
3
通讯作者：
Khajeh, Khosro
中科院分区：
文献类型：
--
作者：
Akbari, Neda;Daneshjoo, Somayeh;Khajeh, Khosro
从一株假单胞菌中分离到一种新的耐有机溶剂的胞外脂肪酶。将脂肪酶基因克隆到大肠杆菌中表达，并通过亲和层析纯化。研究了咪唑类离子液体（EMIM[Cl]、BMIM[Cl]和HMIM[Cl]）对纯化脂肪酶的催化活性。结果表明，经离子液体处理后的脂肪酶在水解反应中的活性高于未经处理的对照。此外，结果表明，酶活性强烈依赖于反应介质中的IL浓度。HMIM[Cl]、BMIM[Cl]和EMIM[Cl]的最佳IL浓度分别为30%、45%和50%（v/v）。此外，该酶在25%的正己烷、甲苯、丙酮和叔丁醇的存在下表现出优异的稳定性。pH和温度的最佳值分别确定为10和55 A度C。K（m）和V（max）值分别计算为0.4 mM和1.92 U/ml，使用棕榈酸对硝基苯基酯作为底物。对于新分离的脂肪酶的生化性质，如高水平的稳定性和显着的活性在有机溶剂和离子液体的存在下，新分离的脂肪酶似乎是一个很好的候选人，在非水介质中进行的环境和工业过程。
A novel extracellular lipase with organic solvent tolerance was isolated from a local Pseudomonas species. The lipase gene was cloned and expressed in Escherichia coli as a heterologous host and purified by affinity chromatography. The activity of purified lipase was investigated in the presence of imidazolium-based ionic liquids (ILs) such as EMIM[Cl], BMIM[Cl], and HMIM[Cl]. It has been found that the activity of treated lipase with ILs was higher than untreated control in the hydrolysis reaction. Also, the results indicated that the enzymatic activity strongly depends on IL concentration in reaction media. The best concentration of the IL was 30%, 45%, and 50% (v/v) for HMIM[Cl], BMIM[Cl], and EMIM[Cl], respectively. Additionally, the enzyme exhibited excellent stability in the presence of 25% of n-hexane, toluene, acetone, and t-butanol. The optimum values of pH and temperature were determined 10 and 55 A degrees C, respectively. The K (m) and V (max) values were calculated 0.4 mM and 1.92 U/ml, respectively, using p-nitrophenyl palmitate as substrate. With respect to the biochemical properties of the newly isolated lipase such as high-level stability and noticeable activity in the presence of organic solvents and ionic liquids, the newly isolated lipase seems to be a good candidate for environmental and industrial processes carried out in non-aqueous media.