聚乙烯醇复合凝胶固定壳聚糖酶的研究

Study on immobilization of chitosanase using a PVA-gelatin carrier system

以聚乙烯醇(PVA)和海藻酸钠复合凝胶为载体,利用反复冻融法固定壳聚糖酶,利用响应面中心复合设计法优化聚乙烯醇与海藻酸钠的浓度,结果分别是10·88%、1·07%,并对游离的壳聚糖酶和固定化酶的特性进行比较,经固定化的酶,其机械性能和化学稳定性都得到显著提高,与游离酶相比,固定化酶的最适反应pH由5·0降至4·5,最适反应温度由60℃升至65℃,其米氏常数由7·24mg/mL升至10·12mg/mL,固定化的酶在连续使用7次后,仍可保持79%的酶活。

Chitosanase were immobilized in polyvinyl alcohol（PVA）and sodium alginate carrier system by a freezing-thawing method.The optimal composition of the PVA and sodium alginate was obtained by central composite design and response surface analysis was 10.88% and 1.07%.And the characteristics of free and immobilized enzyme were compared.The immobilization in cryo PVA-gel stabilized the chitosanase and ensured high mechanical and chemical stability of the biocatalyst.Compared with the free enzyme,the optimum pH value and temperature ofimmobilized chitosanase respectively shifted from 5.0 to 4.5 and from 60℃ to 65℃.And immobilization increased in Km value from 7.24mg/mL to 10.12mg/mL.After seven times repeated batch operation,the relative activity ofimmobilized enzyme was about 79%.