Key Laboratory of Molecular Biophysics, Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology , Wuhan 430074, People's Republic of China.
J Agric Food Chem. 2012 Sep 26;60(38):9673-9. doi: 10.1021/jf301827y. Epub 2012 Sep 11.
Geotrichum sp. lipase (GSL) was first displayed on the cell wall of Pichia pastoris on the basis of the a-agglutinin anchor system developed in Saccharomyces cerevisiae . Surface display levels were monitored using Western blotting, immunofluorescence miscroscopy, and fluorescence-activated cell sorting analysis. Lipase activity of the yeast whole cells reached a maximum at 273 ± 2.4 U/g of dry cells toward olive oil after 96 h of culture at 30 °C, with optimal pH and temperature at 7.5 and 45 °C, respectively. Displayed GSL exhibited relatively high stability between pH 6.0 and 8.0 and retained >70% of the maximum activity. The surface-displayed lipase retained 80% of its original activity after incubation at 45 °C for 4 h. Moreover, the GSL-displaying yeast whole cells were then used as a biocatalyst to enrich eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from fish oil on the basis of selective hydrolysis. As a result, EPA and DHA increased from 1.53 and 24.1% in the original fish oil to 1.85 and 30.86%, which were increases of 1.21- and 1.29-fold, respectively. The total yield of EPA and DHA reached 46.62%.
基于在酿酒酵母中开发的α-凝集素锚定系统，首次将地霉属脂肪酶（GSL）展示在毕赤酵母的细胞壁上。通过 Western blot、免疫荧光显微镜和荧光激活细胞分选分析监测表面展示水平。在 30°C 下培养 96 小时后，酵母全细胞对橄榄油的脂肪酶活性达到最高，为 273±2.4 U/g 干细胞，最适 pH 和温度分别为 7.5 和 45°C。展示的 GSL 在 pH 6.0 至 8.0 之间表现出相对较高的稳定性，保留了>70%的最大活性。固定化脂肪酶在 45°C 下孵育 4 小时后仍保留 80%的原始活性。此外，然后将展示 GSL 的酵母全细胞用作生物催化剂，基于选择性水解从鱼油中富集二十碳五烯酸（EPA）和二十二碳六烯酸（DHA）。结果，EPA 和 DHA 从原始鱼油中的 1.53%和 24.1%分别增加到 1.85%和 30.86%，分别增加了 1.21-和 1.29 倍。EPA 和 DHA 的总产量达到 46.62%。
