Search for and use of enzymes of marine origin for the directed hydrolysis of sulfated polysaccharides

通过仅能水解硫酸酯类多糖的糖苷键的酶，可以产生广谱的生物活性硫酸酯低聚糖。关于这些酶的报道很少，最近只有一组岩藻多糖酶的报道。这种类型的生物催化剂专门用于从褐藻中提取含有岩藻糖的多糖--岩藻多糖。以新近分离到的岩藻聚糖酶阳性真菌Dendryphiella arenaria TM94为出发菌株，进行了酶活性测定、固体发酵初筛、分批培养和下游加工等基础研究。此外，还必须探索在不损失硫酸盐的情况下降解天然岩藻糖胶和生产分子量大于5 kDa的硫酸化低聚物的一般方法。同时，必须研究从不同海洋生境中分离出来的其他微生物以内源性方式降解天然硫酸盐多糖的潜力。在分批和恒化器培养的生化工程实验中，必须挑选出最好的候选者。必须将足够的细胞质量和/或上清液转移到下游加工，以分离所需的酶、其特性，并将其用于生物催化生产硫化低聚糖(相对分子质量大于5 kDa)。随后，必须对低聚物进行生物活性测试。

By means of enzymes capable to hydrolyse only the glycosidic linkages of sulfated polysaccharides, a broad spectrum of bioactive sulfated oligosaccharides should be produced. Reports on these enzymes are scarce; only one group, that of fucoidanases, was reported recently. This type of biocatalyst is specialized on fucose-containing polysaccharides, fucoidans, from brown algae. The fucoidanase-positive fungus Dendryphiella arenaria TM94 (isolated recently) serves as starting strain for basic studies on enzyme assays, initial solid substrate fermentation, batch cultivations and downstream processing. Additionally, the general methods to degrade natural fucoidans without loss of sulgate and to produce sulfated oligomers with molecular weights of more than 5 kDa have to be explored. In parallel, other microorganisms isolated from various marine habitats, have to be studied for their potential to hydrolyze natural sulfated polysaccharides in an endo-type manner. Best candidates have to be choosen for biochemical engineering experiments in batch and chemostat cultivations. Sufficient cell mass and/or supernatant have to be transferred to the downstream processing for isolation of the desired enzymes, their characterization, and their use in biocatalysis for the production of sulgated oligosaccharides (MW more than 5 kDa). Subsequently, the oligomers have to be tested for bioactivities.