利用擠壓米糠澱粉於改變導電度下生產耐鹽菌之紅色色素的研究

Production of Red Pigment of Haloferax mediterranei by Using Extruded Rice Bran and Starch Under Different Conductivity

許淑惠(Shu-Hui Hsu)

指導教授 ： 陳志成

大同大學/工程學院/生物工程學系所/碩士(2004年)

摘要

本研究採用須培養在極高鹽度環境下的Haloferax mediterranei，其不易被雜菌汚染，可降低設計及操作成本，且比較選用葡萄糖與廉價的農業原料經擠壓處理後的米糠澱粉為碳源，於不同導電度下，以pH-stat批次饋料醱酵方式進行培養，以提高菌體濃度及色素產量，並使用丙酮為萃取色素之溶劑，所萃取得之色素其吸光值波峰之圖譜(530, 495和470 nm)近似bacterioruberin。
研究結果發現以擠壓米糠澱粉為碳源培養在導電度3.0 S/m的環境下，能大幅的提昇菌體濃度達117 g/L與色素量為361.4 mg/L，維持導電度在2.5 S/m時，則色素量最高達555.6 mg/L，菌體濃度只達83.5 g/L。證明於低導電度下以擠壓米糠澱粉為碳源有助於色素之大量生成。

關鍵字

色素 ； 嗜鹽菌

並列摘要

Haloferax mediterranei, used in this study is an extremely halophilic bacterium that is not easily contaminated. As a result, costs for sterility and fermentation process can be reduced. In this study two carbon materials – glucose and extruded rice bran/starch which is a cheap agricultural ingredients was compared for the source cost. A pH-stat control strategy is performed in a repeated fed-batch fermentation process under varying conductivity to enhance the cell mass of H. mediterranei and the productivity of red pigment. Acetone was found as an excellent extracting solvent. The extracted pigment shows three peaks of absorbance at 530, 495 and 470 nm that are similar to the absorbance profile of bacterioruberin.
This study found that the fermentation using extruded rice bran/starch as a carbon source can dramatically increase cell mass of H. mediterranei to 117 g/L and pigment concentration to 361.4 mg/L, when the conductivity was controlled around 3.0 S/m. However, when the conductivity was maintained at 2.5 S/m, pigment concentration can reaches 555.6 mg/L even the maximum cell concentration was only with 83.5 g/L. Therefore, we conclude that low conductivity is beneficial for the massive production of pigments.

並列關鍵字

Haloferax mediterranei ； pigment

參考文獻

Asker D. and Ohta Y. 1999. Production of canthaxanthin by extremely halophilic bacteria. Journal of bioscience and bioengineering. 88: 617-621.

Bramley P. M. and Mackenzie A. 1988. Regulation of carotenoid biosynthesis. Curr. Top. Cell. Regul. 29:291-345.

Britton G. 1995. Structure and properties of carotenoids in relation to function. FASEB J. 9:1551-1558.

Britton G., Liaaen-Jensen S. and Pfander, H. (eds). 1998. Carotenoids Volume 3: Biosynthesis and metabolism. Birkhäuser. Switzerland. p. 94-140.

Britton G., Liaaen-Jensen S. and Pfander H. (eds). 1999. Carotenoids Volume 1A: Isolation and analysis. Birkhäuser. Switzerland. p. 13-70.