摘要
以聚乙烯醇(PVA)复合凝胶为载体,利用冻融法固定产α葡萄糖转苷酶的黑曲霉M1菌丝。由于PVA冻胶的多孔性,高分子底物可以穿透载体与细胞酶直接反应。细胞经过固定化后,机械性能和化学稳定性都得到提高,可以重复多次对甲基αD葡萄糖苷进行水解反应。同时对该自由细胞和固定化细胞进行酶学特性研究。发现2者的最适pH值同为pH6.0,最适反应温度分别为55℃、60℃。固定化细胞的Vm值为2.84μmol/(L·min·g),大于自由细胞的Vm1.71μmol/[L·(min·g)],固定化细胞的Km(11.88mmol/L)小于自由细胞的Km(20.50mmol/L)。细胞经固定化,提高了细胞酶的操作、温度和贮藏稳定性。
Aspergillus niger cells produced α-transglucosidase were entrapped in polyvivyl alcohol （PVA）-cryogel beads by a freezing-thawing method. Due to the povosity of PVA-cryogels, high molecular-weight substances can penetrate beads of the biocatalyst. The immobilization in cryoPVA-gel stabilized the cell and ensured high mechanical and chemical stability of the biocatalyst, which could be used many times for α-D-Glucopyranoside hydrolysis. Various characteristics of immobilized cells such as thermal and pH optimum, pH and thermal storage stability were evaluated. Among them the pH optimum of free and immobilized cell were found to 6.0 and the thermal optimum of free cell was 55＇12 whereas that of immobilized cell was 60℃. Immobilization increased in Vm value from 1.71 to 2.84μmol /（L·min·g） （cell） and the Km value of immobilized cell （11.88 mmol/L ） was lower than that of free cell （20.50 mmol/L ）. It was observed that operational, pH, and thermal stabilities of the Membrane-bound enzyme were increased with immobilization.
出处
《食品与发酵工业》
CAS
CSCD
北大核心
2006年第3期33-36,共4页
Food and Fermentation Industries
