環狀糊精( cyclodextrins , CDs)是由6~8個葡萄糖單元,以α-1,4-糖苷鍵結形成的環狀化寡糖。廣泛應用於許多領域,例如醫藥、化妝品、食品工業等。環狀糊精是由是由利用葡萄糖苷轉移酵素催化澱粉而生成。本研究以Bacillus sp. BCRC10094為CGTase 的生產菌株進行搖瓶振盪培養,探討碳源對發酵活性的影響,比較玉米澱粉、木薯澱粉、可溶性澱粉(關東化學株式會社)、麥芽糖、以及 DE10, DE20 的可溶性澱粉(環泰果糖股份有限公司)作為震盪培養的碳源,結果發現使用2 ﹪(w/v)玉米澱粉、木薯澱粉、可溶性澱粉為基質,在 33 ℃、160 rpm下得到 1400 unit/ml 的活性,但使用麥芽糖與DE10, DE20的可溶性澱粉作為碳源, 得到較低的活性。將本研究的酵素與NOVO的商業酵素進行環狀糊精的合成實驗,配製 15% (w/v) 的各種澱粉,以活性250 unit/g-starch 的 Novo 酵素與玉米澱粉在 75 ℃進行澱粉轉化實驗反應 24 小時,結果發現玉米澱粉可得到 33 % 的β - CD。若使用自己發酵的CGTase則需要 1000~2000 unit/g-starch的酵素,反應24小時,可以得到 18 ~23 % 的轉化率,顯示NOVO酵素有很好的熱穩定性。
Cyclodextrins (CDs) are cyclic oligosaccharides composed of 6-8 glucose with α-1, 4-linkages. CDs have been used in food, pharmaceutics, cosmetics industries. CDs are produced by enzymatic catalyzation of cyclodextrin glucanotransferase (CGTase) from starch. In this study, CGTase is produced using starch or starch hydrolyzates as carbon sources from a Bacillus sp. BCRC 10094. The maximum CGTase activity was about 1400 unit/ml in a shaking culture using 2%(v/w)corn starch, cassava starch, soluble starch (Kanto Chemical Co. Ltd) at 33℃and 160 rpm. The carbon sources using DE10, DE20 soluble starch (Taiwan Fructose Co.,Ltd) and maltose in the medium produced less CGTase activity. The CGTase of this study and commercial CGTase (NOVO) were employed to produce CDs from 15 % (w/v) starch. CDs were produced from corn starch catalyzed by CGTase (NOVO, 250 unit/g-starch) at 75 C for 24 hrs. The yield of CDs from starch was 33 %. However, it was 1000 ~ 2000 unit needed per gram of starch for the CGTase cultured from Bacillus sp. BCRC 10094 in this study. The yield of CDs from starch was 18 ~23 % using our enzyme. The results indicated that CGTase from NOVO had better thermal stability.
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