Zheng Yuan, Wang Zhipeng, Ji Xiaofeng, Sheng Jun
Laboratory of Enzyme Engineering, Yellow Sea Fisheries Research Institute, Qingdao, 266071 People's Republic of China.
3 Biotech. 2019 May;9(5):179. doi: 10.1007/s13205-019-1713-9. Epub 2019 Apr 17.
Isomaltulose (α-d-glucopyranosyl-1,6-d-fructofuranose) is an important industrial and raw food material, which can be synthesised from the by-products of sugar cane processing through sucrose isomerization conversion. In this study, we constructed a surface display vector of sucrose isomerase from (SIase) by a glycosylphosphatidylinositol (GPI)-cell wall protein (CWP) anchor signal sequence and successfully displayed SIase on the cell surface of thereby increasing the conversion efficiency of isomaltulose. The highest activity of the displayed SIase reached 2910.3 U/g of cell dry weight. Compared with the free SIase, the displayed enzyme showed good stability at a broad range of temperatures (20-45 °C). The half-life at 40 °C increased from 62 to 141 min and the deactivation constants ( ) reached 4.91 × 10 min. Using low-cost cane molasses as the substrate, the isomaltulose conversion rate remained at 85% even after 9 batches were processed, which is a highly desired outcome for industrial use.
异麦芽酮糖（α - d - 吡喃葡萄糖基 - 1,6 - d - 呋喃果糖）是一种重要的工业和食品原料，可通过蔗糖异构化转化从甘蔗加工副产品中合成。在本研究中，我们通过糖基磷脂酰肌醇（GPI）- 细胞壁蛋白（CWP）锚定信号序列构建了来自[具体来源未给出]的蔗糖异构酶（SIase）表面展示载体，并成功地将SIase展示在[具体微生物名称未给出]的细胞表面，从而提高了异麦芽酮糖的转化效率。展示的SIase的最高活性达到2910.3 U/g细胞干重。与游离SIase相比，展示的酶在较宽温度范围（20 - 45°C）内表现出良好的稳定性。在40°C下的半衰期从62分钟增加到141分钟，失活常数（）达到4.91×10分钟。以低成本的甘蔗糖蜜为底物，即使经过9批次处理，异麦芽酮糖转化率仍保持在85%，这是工业应用中非常理想的结果。
