Productin of functional galacto-oligosccharides using transfer action of -galactosidase

乳糖与其他钙离子相比溶解性较低。这些性质是使用牛奶和干酪乳清生产食品和食品添加剂的缺点。为了增加双歧因子的功能并克服上述缺点，本研究旨在利用环状芽孢杆菌的β-半乳糖苷酶1（-gal 1）和β-半乳糖苷酶2（-Gal 2）有效地生产低聚半乳糖，这两种酶分别具有水解乳糖和水解乳糖以及合成低聚半乳糖的高活性。本论文主要研究了以下几个方面的问题：1.化学修饰法提高-gal 1的低聚糖形成能力; 2. -Gal 1和2的固定化及其性质的研究; 3.固定化酶在连续反应中的稳定性; 4.采用Prug流动反应器和膜反应器进行低聚糖的长期连续生产; 5.对低聚糖的保护 ...更多信息 用0.01-3%的戊二醛对-Gal 1进行处理，使酶上的氨基含量从0%改性到90%。随着改性程度的增加，形成含葡萄糖残基的聚合度为2 - 5的低聚半乳糖的能力增加，乳糖的低聚糖产率达到40%，氨基修饰90%。将-Gal 2或-Gal 1吸附在各种载体上，用戊二醛交联固定化.在所测试的载体中，Merckogel就活性和稳定性而言是最合适的。固定化酶的比活力越高，越容易可逆失活。这种现象的原因是由于在交联酶的三维网络中产生的寡糖的截留。在PFR中用Merckogel SI-500（15 U/g）上的固定化酶和在膜反应器（Diaflo细胞，UF-X50）中用游离酶连续生产寡糖8天而不使酶失活，并且从20%乳糖的寡糖产率保持在47.5%。通过对牛奶蛋白的吸附-脱附实验，寻找了一种既能防污染又能清洗的载体。与污染物同号电荷的离子交换剂是有效的。提出了采用大载体、高流速的方法来抑制微生物生长的建议。少

Lactose is less soluble compared with other saccharides and tras calcium ion. These properties are the demerit in the food manufacturing and the food additive production using milk and chese whey. To add a function as bifidus factor as well as to diminish the above demerit, the preseht study aimed at the effective production of galacto-oligosaccharides using -galactosidase 1( -gal 1) and -galactosidase 2 ( -Gal 2) from Bacillus circulans which have high activity for hydrolysis of lactose and for hydrolysis of lactose and for synthesis of galactooligosaccharide, respectively. To accoplish the purpose, the following were the particular subjects.1.The enhancement of oligosaccharide formation ability of -gal 1 by chemical modification.2.Immobilization of -Gal 1 and 2 and elucidation of their properties.3.The stability of immobilyzed enzyme during continuous reaction.4.Long term continuous oligosuccharide production using either prug flow reactor or membrane reactor.5.Protection against con … More tamination and cleaning of immobilized enzyme column reactor.By treating the -Gal 1 with 0.01-3% glutaraldehyde, the amino group on the enzyme was modified from 0 to 90%. With increase in modification, increased the ability to form galacto-oligosaccharides of degree of polymerization two to five containing a glucose residue and yield of oligosaccharide from lactose reached to 40% with amino group modification 90%. Either -GAl 2 or -Gal 1 was adosorbed on to various suports and immobilized by glutaraldehyde crosslinking. Among the supports tested, Merckogel was most suitable with respect to activity and stability. however higher the specific activity, easer the immobilized enzyme deactivated reversibly. The reason for this phenomena was ascribed to the entrapment of oligosaccharides produced in the three dimensional network of crosslinked enzymes. Continuous oligosaccharide production was performed in PFR with immobilized enzyme on to merckogel SI-500(15U/g) and in membrane reactor(Diaflo cell, UF-X50) with free enzyme for 8 days without enzyme inactivation and the oligosaccharide yield from 20% lactose was maintained at 47.5%. From the adsorption-desorption experiments of milk protein, the support suitable with respect to the protection of contamination and cleaning was searched. Ion exchanger with the charge of same sign as contaminant was effective. The suggestion was obtained that the growth of micro-organism was reduced by usinglarge support with high flow rate. Less