| Abstract: | 本研究是以蟹殼幾丁質(chitin)和 chitopearl為擔體固定化幾丁聚醣 (chitosanase) ，探討酵素固定化之條件及固定化之性質，並以固定化幾 丁聚醣 進行批式和連續式生產幾丁聚醣水解物之比較，所得不同水解程 度之幾丁聚醣，探討其對不同病原菌之抗菌效果。在固定化酵素方面，利 用幾丁質為擔體，以40-60 mesh 幾丁質、 0.75% 戊二醛及酵素濃度 3.6 mg protein/g chitin 之條件進行幾丁聚糖 之固定化較適宜。另外 利用chitopearl為擔體，以酵素濃度4.8 mg protein/g chitopearl之條 件下進行幾丁聚醣之固定化為佳。利用幾丁質固定化幾丁聚醣 水解幾丁 聚醣，在批式水解方面，以反應溫度50℃和固定化酵素濃度2.0%(dw/v)之 條件為佳。在連續式水解方面，以圓柱反應器，內裝2.0g(dw)固定化酵素 時，流速10mL/hr和反應溫度30℃之條件進行水解為佳。在抗菌效果方面 ，幾丁聚醣及其水解物對四株病原菌(B.cereus，S .aureus，S.typhi及 E.coli)之抗菌效果以水解5%之幾丁聚醣抗菌效果最好。水解10%以上者雖 抗菌較差，但可增加其添加濃度亦可達到其抗菌效果。此外，其水溶性良 好且無澀味，因此在食品之利用更廣。
The studies were focused on: firstly,investigation of opti- mum conditions for immobilization of chitosanase on crab chitin and on chitopearl; secondly,comparison of batch-wise or contin- uous-type hydrolysis of chitosan by the immobilized chitosanases ;and thirdly,comparison of the effect of chitosan and chitosan hydrolyzates on the growth of some bacteria. The suitable conditions for immobilizing chitosanase on chitin were using 40-60 mesh chitin particle size,and treating it with 0.75% glutaraldehyde solution before mixing with 3.6 mg protein/ g chitin..As to the suitable conditions for immobiliz- ing chitosanase on chitopearl were using 4.8 mg protein/g chitopearl. The suitable conditions for the batch-wise hydrolysis of chitosan with the chitin-immobilized chitosanase were a react- ion temperature of50℃,and an immobilized enzyme concentration of 2.0%(dw/v).As to the continuous process,in a column reactor packed with 2.0g(dw) of the immobilized enzyme, the most suit- able conditions for hydrolyzing chitosan were a flow rate 10mL /hr and reacction temperature of 30℃. As to the antibacterial effect of chitosan and chitosan hydrolyzates on some bacteria(E.coli,S.typhi,S.sureus,B.cereus) ,a chitosan hydrolyzate of 5% hydrolyzing degree showed an eff- ect stronger than chitosan and chitosan hydrolyzates of 10%,20% ,30% hydrolyzing degree,orderly,at the same concentration.Alth- ough chitosan hydrolyzates of higher hydrolyzing degree showed lower antibacterial effect than one of 5% hydrolyzing degree and chitosan at low concentration,they presented good effect at higher concentration.On other hand,chitosan hydrolzsates of 10% (or higher)hydrolyzing degree had water-soluble,low viscous, astrigentless taste properties those were usefully in food applications. |
