Isofloridoside (D-isofloridoside and L-isofloridoside) is the main photosynthetic product in red algae. Here, given the importance of isofloridoside, a potentially effective method to produce isofloridoside from galactose and glycerol using whole-cell biocatalysts harboring α-galactosidase was developed. α-Galactosidase-encoding genes from Alicyclobacillus hesperidum, Lactobacillus plantarum, and Bifidobacterium adolescentis were cloned and the proteins were overproduced in Escherichia coli. The α-galactosidase from A. hesperidum (AHGLA) was chosen to synthesize isofloridoside. The effects of reaction pH, temperature, and substrate concentration were investigated. In the optimum biotransformation conditions, the final isofloridoside concentration reached 0.45 M (galactose conversion 23 %). The reaction mixtures were purified using activated charcoal and calcined Celite, and the purified product was identified as a mixture of D- and L-isofloridoside by liquid chromatography-mass spectrometry and nuclear magnetic resonance. This study provides a possible feasible method for the biosynthesis of isofloridoside from low-cost glycerol and galactose.

中文翻译：

---

使用橙皮脂环杆菌的α-半乳糖苷酶从半乳糖和甘油生产异氟烷苷

Isofloridoside（D-isofloridoside 和 L-isofloridoside）是红藻中的主要光合产物。在这里，考虑到异氟烷苷的重要性，开发了一种使用含有 α-半乳糖苷酶的全细胞生物催化剂从半乳糖和甘油生产异氟烷苷的潜在有效方法。来自橙皮脂环杆菌、植物乳杆菌和青春双歧杆菌的α-半乳糖苷酶编码基因被克隆，并且蛋白质在大肠杆菌中过量产生。选择橙皮苷 (AHGLA) 的 α-半乳糖苷酶合成异氟醚苷。研究了反应pH、温度和底物浓度的影响。在最佳生物转化条件下，最终异氟醚苷浓度达到 0.45 M（半乳糖转化率为 23%）。反应混合物用活性炭和煅烧硅藻土纯化，纯化产物经液相色谱-质谱和核磁共振鉴定为D-和L-异氟烷苷的混合物。该研究为低成本的甘油和半乳糖生物合成异氟烷苷提供了一种可行的方法。