Elçin Y M
Chemistry Department, Ankara University, Tandoğan, Turkey.
Biomaterials. 1995 Oct;16(15):1157-61. doi: 10.1016/0142-9612(95)93580-7.
Urease-containing xanthan-alginate spheres were prepared by a two-step process which involved the Ca2+ coupling of the polysaccharides, followed by gentle glutaraldehyde cross-linking with amine groups of gelatin present in the initial mixture. This second step caused a slight decrease in the enzymatic activity but increased the stability. The water content and size distribution of the spheres were examined together with the sphere morphology. The effect of polymer ratio and enzyme loading on urease activity was investigated. An increase in xanthan content was found to affect the water uptake of the spheres. Temperature and pH stability of encapsulated urease was found to be higher than the free form. The xanthan-alginate spheres showed 75% of maximum urease activity even after 20 repeated uses under optimal conditions.
含脲酶的黄原胶-海藻酸盐微球通过两步法制备，该方法包括多糖的Ca2+偶联，随后与初始混合物中存在的明胶胺基进行温和的戊二醛交联。第二步导致酶活性略有下降，但增加了稳定性。对微球的含水量、尺寸分布以及微球形貌进行了研究。考察了聚合物比例和酶负载量对脲酶活性的影响。发现黄原胶含量的增加会影响微球的吸水率。包封脲酶的温度和pH稳定性高于游离形式。即使在最佳条件下重复使用20次后，黄原胶-海藻酸盐微球仍显示出75%的最大脲酶活性。
