University of Hohenheim, Institute for Food Science and Biotechnology, Department of Biotechnology, Garbenstr. 25, 70599 Stuttgart, Germany.
J Biotechnol. 2010 Feb 15;145(4):387-93. doi: 10.1016/j.jbiotec.2009.12.017. Epub 2009 Dec 29.
A continuous enzymatic process for the production of the prebiotic disaccharide lactulose through transgalactosylation was developed using free and immobilized beta-glycosidase from Pyrococcus furiosus. The hyperthermostable beta-glycosidase (CelB) was immobilized onto an anion-exchange resin (Amberlite IRA-93) or onto Eupergit C with immobilization yields of 72% and 83%, respectively. The immobilized biocatalysts demonstrated specific activities of 920 nkat g(-1) dry carrier and 1500 nkat g(-1) dry carrier at 75 degrees C with p-nitrophenyl-beta-D-galactopyranoside as substrate. Continuous biotransformations in packed-bed reactors using carrier bound CelB and in an enzyme membrane reactor using free CelB were carried out at 75 degrees C. Maximum lactulose yields of 43% related to the initial lactose concentration were reached with the carrier bound CelB preparations. The corresponding productivities were 52 glactulose l(-1)h(-1) (Amberlite IRA-93) and 15 glactulose l(-1)h(-1) (Eupergit C), respectively. The free enzyme tested in an enzyme membrane reactor showed a product yield of 41% and a productivity of 12 glactulose l(-1)h(-1) in the first day. While both carrier bound CelB preparations were 100% stable for at least 14 days, the half-life of the free CelB in the enzyme membrane reactor was only about 1.5 days.
开发了一种通过转半乳糖作用连续生产益生元低聚半乳糖的酶法工艺，使用来自 Pyrococcus furiosus 的游离和固定化β-糖苷酶。超耐热β-糖苷酶（CelB）分别固定在阴离子交换树脂（Amberlite IRA-93）或 Eupergit C 上，固定化收率分别为 72%和 83%。固定化生物催化剂在 75°C 下以 p-硝基苯-β-D-半乳糖吡喃糖苷为底物，具有 920 nkat g-1干载体和 1500 nkat g-1干载体的比活性。在 75°C 下，使用载体结合的 CelB 在填充床反应器中进行连续生物转化，以及使用游离 CelB 在酶膜反应器中进行连续生物转化。使用载体结合的 CelB 制剂达到了与初始乳糖浓度相关的最大低聚半乳糖产率 43%。相应的生产率分别为 52 glactulose l-1h-1（Amberlite IRA-93）和 15 glactulose l-1h-1（Eupergit C）。在酶膜反应器中测试的游离酶在第一天显示出 41%的产物产率和 12 glactulose l-1h-1的生产率。虽然两种载体结合的 CelB 制剂在至少 14 天内都保持 100%稳定，但游离 CelB 在酶膜反应器中的半衰期仅约为 1.5 天。
