利用生產lovastatin之AspergillusterreusATCC20542之醱酵過程中，探討溶氧對其共同代謝物itaconicacid生產之影響

Effects of DO on the production of itaconic acid by a lovastatin-producing fungus Aspergillus terreus ATCC 20542

洪鳳鳴(Feng-ming Hung)

指導教授 ： 賴龍山

朝陽科技大學/理工學院/應用化學系/碩士(2008年)

摘要

本研究是利用真菌Aspergillus terreus ATCC 20542在28oC之二階段培養、並以5升醱酵槽之溶氧(DO)控制來檢測代謝物IA與lovastatin之生產(含兩者之消長關係)。實驗發現在不同的、但全程固定的DO控制條件下，IA與lovastatin之產量均以DO 20%之為最佳，其他產量依序為DO 30%、DO 40%、DO 10%，而且各控制條件下IA與lovastatin之產量均呈類比關係，暗示IA在此菌株代謝過程可能扮演合成lovastatin或提供官能基團的角色。進一步在不同時機溶氧控制(即DO 20% at 0-144 h)，在非0 h而在其他時機啟動的實驗組中發現醱酵液溶氧供應不足(即DO 2-5%)，此現象會使得液中pH值不升反降，可能因而導致代謝物(指IA或 lovastatin)生產之變動；此外，本研究也發現醱酵初期溶氧可使用率對此真菌代謝物IA生產之效應遠大於對lovastatin合成的影響。

關鍵字

土黴菌 ； 衣康酸 ； Lovastatin ； 溶氧

並列摘要

Effects of DO on the production of co-metabolite, itaconic acid (IA), were investigated in the study, where a two-stage culture of Aspergillus terreus ATCC 20542 (a lovastatin-producing fungus) was conducted in a 5 L fermentor at 28oC. Both of the production of IA and lovastatin were optimized under a constant control of DO 20%, followed by DO 30%, DO 40% and DO 10%. The results implied that IA might play a role or act as a donor in the lovastatin synthesis by the fungus because a proportional production kinetics was found when the above mentioned DO control was applied. Furthermore, in the experiments of “DO 20% if initiated at a different timing (0-144 h)”, DO depletion (DO 2-5%) was observed at earlier stages of the fermentation; meanwhile, such a DO control was applied starting from 48-144 h. It was found that the fermentation broth pH was decreased, rather than increased; therefore, it night be possible that cell growth or metabolite production (IA or lovastatin) could thus be changed because of such alternation. Besides, effects of DO availability, especially in earlier stages, on the synthesis of IA had a much higher impact than that of lovastatin.

並列關鍵字

itaconic acid ； dissolved oxygen (DO) ； Aspergillus terreus ； lovastatin

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