醱酵生產環狀糊精葡萄糖苷轉移酶及生產環狀糊精反應條件之探討

Production of Cyclodextrin Glucanotransferase and Reaction Conditions to Produce Cyclodextrins

陳靜怡(Jing-Yi Chen)

指導教授 ： 段國仁

大同大學/工程學院/生物工程學系所/碩士(2009年)

摘要

環狀糊精葡萄糖苷轉移酶Cyclodextrin glucanotransferase (CGTase)是具有將澱粉轉換成環狀糊精分子的酵素，本研究使用alkalophilic Bacillus sp. (ATCC 21595)菌種以麥芽糊精(DE10)為碳源進行醱酵生產環狀糊精轉移酶，在搖瓶培養中，以2%麥芽糊精(DE10)(C：N=1：1)為碳源，得到CGTase活性為6099 unit/ml，用醱酵槽醱酵則得到活性為19540 unit/ml。將培養基的碳源麥芽糊精(DE10)(C：N=2：1)進一步提升到10%，得到的CGTase活性為48580 unit/ml。
以環狀糊精轉移酶將澱粉進行環化反應生成環狀糊精，以2000 unit/g-starch CGTase進行反應，對於5%、10%、15%玉米澱粉轉換率分別為42.8%、27.3%、20.4%，以低濃度澱粉反應有高轉換率。15%玉米澱粉以1000 unit/g-starch CGTase反應，在75℃反應轉換率最高達16.3 %，為了降低環狀糊精生產的成本，先在澱粉液化的階段使用α-amylase進行玉米澱粉的水解，澱粉水解後再加入環狀糊精葡萄糖苷轉移酶，酵素的劑量為CGTase 1000 unit/g-starch，轉換率則可達20 %。
在環狀糊精轉移酶之乾燥方面，以冷凍乾燥方式，環狀糊精轉移酶可達84%殘餘活性。以噴霧乾燥方式，出口溫度分別設定在90 ℃仍保有80%殘餘活性。

關鍵字

噴霧乾燥 ； 環狀糊精 ； 環狀糊精葡萄糖苷轉移酶 ； 冷凍乾燥

並列摘要

Cyclodextrins can be synthesized by cyclodextrin glycosyltransferase (CGTase) from starch. The present investigation employed an alkalophilic Bacillus sp. (ATCC 21595) to produce CGTase using soluble starch (DE10) as carbon source in the fermentation process. The activity of 6099 by the shaking culture and 19540 unit/ml by the batch fermentation were achieved using 2% (w/v) DE10 as carbon source (C:N=1:1). Furthermore, another fermentation using 10% (w/v) DE10 (C:N=2:1) as carbon source was conducted to achieve 48580 unit/ml.

In the production of cyclodextrin, 5, 10, 15 % (w/v) of the corn starch (2000 unit/g starch) was used, and the conversion yield of 0.43, 0.27, 0.20 respectively (g -cyclodextrin/g corn starch) was obtained. Higher conversion yield was obtained in lower starch concentration. To reduce the cost of CGTase, 1000 unit/g starch was used to achieve the conversion yield of 0.16. However, the conversion yield could increase to 0.2 using 1000 unit/g starch when -amylase was used in the starch liquefaction process.

The CGTase was freeze dried to retain 84% of the residual activity. Spray drying was also conducted remove water content of the CGTase, 80% residual activity was obtained when the outlet gas temperature was set at 90 C.

並列關鍵字

Spray drying ； cyclodextrin ； Cyclodextrin glycosyltransferase (CGTase) ； Freeze dried

參考文獻

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