Immobilization of lipase on methyl-modified silica aerogels by physical adsorption.
Immobilization of lipase on methyl-modified silica aerogels by physical adsorption.
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DOI：
10.1016/j.biortech.2008.06.060
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发表时间：
2009
影响因子：
11.4
通讯作者：
Siliang Gao;Yujun Wang;Tao Wang;G. Luo;You-yuan Dai
中科院分区：
文献类型：
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作者：
Siliang Gao;Yujun Wang;Tao Wang;G. Luo;You-yuan Dai
本文以甲基改性二氧化硅气凝胶这一新型大孔材料为载体，通过吸附的方法固定化脂肪酶。采用扫描电子显微镜、透射电子显微镜、氮气吸附装置和热重分析等手段对改性气凝胶的性能进行了表征。比表面积为395.6m2/g，平均孔径为68.72 nm。气凝胶颗粒经甲基修饰后，接触角由20.9°增加到99.2°。讨论了酶负载后材料的反应特性。结果表明，其吸附容量可达67.42 mg/g，最大酶活为19.87molminμ−1 mg−1(蛋白质)，活性保留率可达56.44%。值得一提的是，改性气凝胶的加入量对反应乳状液中的液滴直径和基质的传质行为有显著影响。用在线显微镜观察乳状液中的液滴，观察到气凝胶颗粒位于油和水的界面。在含有10ml油和10ml磷酸盐缓冲溶液的反应乳状液中加入0.06g改性气凝胶时，液滴的平均直径最小。这一现象是由甲基改性二氧化硅气凝胶的润湿性引起的。
In this work, methyl-modified silica aerogels, a new kind of macro-porous material with high porosity, were used as carriers to immobilize lipase by adsorption. SEM, TEM, nitrogen adsorption device, and thermogravimetric analysis were used to characterize the properties of modified aerogels. The surface area was 395.6m2/g, and the average pore diameter was 68.72nm. The contact angle of aerogel particles increased from 20.9° to 99.2° after methyl modification. Reaction characteristics of the material after enzyme loading were also discussed. The results showed that adsorption capacity could reach 67.42mg/g; and the maximal enzyme activity was 19.87μmolmin−1mg−1(protein), and activity retention could reach 56.44%. It is worth mentioning that the amount of modified aerogels added had significant effects on the diameter of droplets and the mass transfer behavior of substrates in the reaction emulsion. Online microscope was used to visualize the droplets in the emulsion, where the aerogel particles were observed locating at the interface of oil and water. The average diameter of droplets reached the minimum when 0.06g of modified aerogels was added into the reaction emulsion which contained 10ml of oil and 10ml of phosphate buffer solution. The phenomenon was resulted from the wettability of methyl-modified silica aerogels.