- 學位論文
不分解蔗糖、麥芽糖或乳糖的酵母菌的篩選
The Screening of Yeasts That Do Not Utilize Sucrose, Maltose or Lactose
摘要
有鑑於目前市售的低純度果寡糖、異麥芽寡糖和半乳寡糖糖漿內容物，除了寡醣的主成份外，大都還含有大量葡萄糖以及相當量的其它反應不完全的原料糖，例如：蔗糖、麥芽糖或乳糖等人體可消化糖，為了去除寡糖糖漿內的可消化糖，又不要減少寡醣的產量，達到純化出高純度寡糖漿的目的，因而想到在反應過程中，利用酵母菌對糖的醱酵具有選擇性，在不影響反應物的前題下以酵母菌醱酵法將反應過程中的葡萄糖去除，來提高產品中寡醣的含量，就可以提升寡醣的保健功能及商品價值，即篩選「不分解蔗糖、麥芽糖或乳糖的酵母菌」來達到此目標。將酵母菌培養於含有酵母萃取物、葡萄糖以及蔗糖、麥芽糖或乳糖的培養基中，然後用高效液相層析法分析殘存的醣類，以篩選出只消耗葡萄糖，而不分解蔗糖、麥芽糖或乳糖的酵母菌。在所篩選的酵母菌之中，Wickerhamomyces anomala BCRC 20858、Candida utilis BCRC 21990可代謝蔗糖，而不會利用麥芽糖和乳糖。另外，Pichia bimundalis BCRC 20479可輕微代謝乳糖，而Wickerhamomyces anomalus BCRC 20866則對於蔗糖、麥芽糖、乳糖都不會代謝。這些酵母菌都有潛力，將可利用於高純度寡糖的製造。
並列摘要
The low-content oligosaccharides including fructooligisaccharides (FOS), isomaltooligosaccharides (IMO) and galactooligosaccharides (GOS) consisted of not only oligosaccharides but also large amount of glucose and unreacted substrate sugars, such as sucrose, maltose and lactose. In order to eliminate these digestible sugars from oligosaccharides syrups and to increase the yields of oligosaccharides, selected yeasts were employed during the enzymatic reactions for the production of oligosaccharides. These yeasts should consume glucose alone but not the substrate sugars. During the oligosaccharides-forming reaction catalyzed by enzyme and yeast, the byproducts glucose was concurrently eliminated by yeast fermentation. This work was engaged in the screening of such yeasts that can ferment glucose but not sucrose, maltose or lactose. Yeasts were cultured in the fermentation medium composed of yeast extract, glucose and sucrose, maltose or lactose. Then the sugars in the fermented broth were analyzed by HPLC. Among four yeast strains, Wickerhamomyces anomala BCRC 20858 and Candida utilis BCRC 21990 could utilize sucrose but not maltose and lactose and Pichia bimundalis BCRC 20479 consume lactose slightly, whereas Wickerhamomyces anomalus BCRC 20866 did not utilize three sugars at all.