Abstract：
Alginates are valued in many industries, due to their versatile properties. These polysaccharides originate from brown algae (Phaeophyceae) and some bacteria of the Azotobacter and Pseudomonas genera, consisting of 1 → 4 linked β-d-mannuronic acid (M), and its C5-epimer α-l-guluronic acid (G). Several applications rely on a high G-content, which confers good gelling properties. Because of its high natural G-content (FG = 0.60-0.75), the alginate from Laminaria hyperborea (LH) has sustained a thriving industry in Norway. Alginates from other sources can be upgraded with mannuronan C-5 epimerases that convert M to G, and this has been demonstrated in many studies, but not applied in the seaweed industry. The present study demonstrates epimerisation directly in the process of alginate extraction from cultivated Saccharina latissima (SL) and Alaria esculenta (AE), and the lamina of LH. Unlike conventional epimerisation, which comprises multiple steps, this in-process protocol can decrease the time and costs necessary for alginate upgrading. In-process epimerisation with AlgE1 enzyme enhanced G-content and hydrogel strength in all examined species, with the greatest effect on SL (FG from 0.44 to 0.76, hydrogel Young\'s modulus from 22 to 34 kPa). As proof of concept, an upscaled in-process epimerisation of alginate from fresh SL was successfully demonstrated.
摘要：
海藻酸盐在许多行业都很有价值，由于其多才多艺的性质。这些多糖起源于褐藻（Phaeophyceae）和一些固氮菌和假单胞菌属的细菌，由1→4连接的β-d-甘露糖醛酸(M)组成，及其C5-差向异构体α-1-古洛糖醛酸(G)。一些应用程序依赖于高G含量，这赋予了良好的胶凝性能。由于其天然G含量高（FG=0.60-0.75），海带藻酸盐（LH）在挪威保持了蓬勃发展的产业。来自其他来源的藻酸盐可以使用将M转换为G的MannuronanC-5差向异构酶进行升级，这已经在许多研究中得到了证明，但不适用于海藻行业。本研究表明，在从栽培的isabissima（SL）和Alariaesculenta（AE）的藻酸盐提取过程中直接进行了差向异构化，和LH的椎板。与传统的差向异构化不同，包括多个步骤，该过程中的方案可以减少藻酸盐升级所需的时间和成本.用AlgE1酶进行的过程中差向异构化提高了所有检查物种的G含量和水凝胶强度，对SL的影响最大（FG从0.44到0.76，水凝胶杨氏模量从22到34kPa）。作为概念的证明，成功地证明了从新鲜SL中对海藻酸盐进行了大规模的过程中差向异构化。
