An Jin, Zhang Lebin, Li Lijuan, Liu Dawen, Cheng Huiling, Wang Hengwei, Nawaz Muhammad Zohaib, Cheng Hairong, Deng Zixin
State Key Laboratory of Microbial Metabolism and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University , Shanghai 200240, China.
Innovation & Application Institute, Zhejiang Ocean University , Zhoushan 316022, China.
J Agric Food Chem. 2016 May 18;64(19):3819-27. doi: 10.1021/acs.jafc.5b06138. Epub 2016 May 6.
An alternative strategy for synthesizing galactooligosaccharides (GOS) from an erythritol-producing yeast Yarrowia lipolytica using surface display technology was demonstrated. The engineered strain CGMCC11369 was developed by fusion of the β-galactosidase gene from Aspergillus oryzae to the YlPir1 gene, which codes for a cell wall protein. β-Galactosidase was effectively displayed on the cell surface of Yarrowia lipolytica start strain CGMCC7326. This engineered strain with surface-displayed β-galactosidase efficiently synthesized GOS from lactose. An amount of 160 g/L GOS was produced within 6 h in a solution of 500 g/L lactose and 5 mg/mL cell (dry weight) at pH 5.5 and 60 °C, with a yield of 51% of consumed lactose monohydrate. This newly developed method was applied with waste yeast paste from erythritol industry at least 10 times. The optimal reaction temperature increased to 60 °C, about 20 °C higher than that of free β-galactosidase, which was helpful for enhancing the reaction rate and GOS production.
展示了一种利用表面展示技术从产赤藓糖醇的解脂耶氏酵母合成低聚半乳糖（GOS）的替代策略。通过将米曲霉的β-半乳糖苷酶基因与编码细胞壁蛋白的YlPir1基因融合，构建了工程菌株CGMCC11369。β-半乳糖苷酶有效地展示在解脂耶氏酵母起始菌株CGMCC7326的细胞表面。这种表面展示β-半乳糖苷酶的工程菌株能有效地从乳糖合成GOS。在pH 5.5和60℃条件下，于500 g/L乳糖和5 mg/mL细胞（干重）的溶液中，6小时内可产生160 g/L GOS，消耗的乳糖一水合物产率为51%。这种新开发的方法至少应用于赤藓糖醇工业的废酵母膏10次。最佳反应温度提高到60℃，比游离β-半乳糖苷酶的温度高约20℃，这有助于提高反应速率和GOS产量。
