Talukder Mahabubur Rahman, Susanto Diana, Feng Gao, Wu Jinchuan, Choi Won Jae, Chow Yvonne
Institute of Chemical and Engineering Sciences, Singapore, Singapore.
Biotechnol J. 2007 Nov;2(11):1369-74. doi: 10.1002/biot.200700099.
Reverse micelles are formed in apolar solvents by spontaneous aggregation of surfactants. Surfactant sodium bis (2-ethylhexyl) sulfosuccinate (AOT) is most often used for the reverse micellar extraction of enzymes. However, the inactivation of enzyme due to strong interaction with AOT molecules is a severe problem. To overcome this problem, the AOT/water/isooctane reverse micellar system was modified by adding short chain polyethylene glycol 400 (PEG 400). The modified AOT reverse micellar system was used to extract Mucor javanicus lipase from the aqueous phase to the reverse micellar phase. The extraction efficiency (E) increased with the increase in PEG 400 addition and the maximum E in PEG 400 modified system was twofold higher than that in the PEG 400-free system. Upon addition of PEG 400, the water activity (a(w)) of aqueous phase decreased, whereas a(w) of reverse micellar phase increased. The circular dichroism spectroscopy analysis revealed that PEG 400 changes the secondary and tertiary structure of lipase. The maximum specific activity of lipase extracted in PEG 400-modified reverse micellar system was threefold higher than that in the PEG-free system.
反胶束是由表面活性剂在非极性溶剂中自发聚集形成的。表面活性剂双（2-乙基己基）磺基琥珀酸钠（AOT）最常用于酶的反胶束萃取。然而，由于与AOT分子的强烈相互作用导致酶失活是一个严重的问题。为了克服这个问题，通过添加短链聚乙二醇400（PEG 400）对AOT/水/异辛烷反胶束体系进行了改性。改性后的AOT反胶束体系用于将爪哇毛霉脂肪酶从水相萃取到反胶束相。萃取效率（E）随着PEG 400添加量的增加而提高，PEG 400改性体系中的最大E比无PEG 400体系高两倍。添加PEG 400后，水相的水分活度（a(w)）降低，而反胶束相的a(w)增加。圆二色光谱分析表明，PEG 400改变了脂肪酶的二级和三级结构。在PEG 400改性反胶束体系中萃取的脂肪酶的最大比活性比无PEG体系高两倍。
