利用Aspergillus niger自廢棄龍眼核回收及轉化合成鞣花酸之生產策略探討

A study on the production of ellagic acid using the longan seed as substrate by Aspergillus niger

許靖佳(Ching-Cha Hsu)

指導教授 ： 魏毓宏

元智大學/工程學院/生物科技與工程研究所/碩士(2012年)

摘要

鞣花酸(Ellagic acid, EA)為一種存在於植物中之多酚類化合物，具有美白、抗氧化、抗癌、抗突變及消炎的活性，預期在化妝品及醫藥產業等應用方面皆具有良好的開發前景。植物可自體生成鞣花酸並將其轉化為鞣花單寧(ellagitinnin)、沒食子酸(gallic acid)或其他衍生物，因此可直接從植物中萃取出鞣花酸，或是先萃取出鞣花單寧，再利用降解方式來生產鞣花酸。
中國大陸、泰國及台灣是全世界龍眼(longon)主要產區，其中有一半龍眼供鮮食，另一龍眼經去核加工可製成桂圓，不管是做為鮮食或桂圓食品製造過程中，將產生大量之龍眼核(longon seed)，龍眼核都會被當成農業廢棄物丟棄。文獻指出：龍眼核內含大量的植物多酚類化合物，如鞣花酸、鞣花單寧及沒食子酸。若能夠利用此廢棄物來生產鞣花酸，將符合廢棄物回收利用並提高其經濟效益之雙重目的。
本研究首先探討不同萃取方式對從龍眼核回收鞣花酸之影響，進而配合微生物降解法將萃取出之鞣花單寧降解為鞣花酸。研究結果顯示：以50%乙醇溶劑為最佳之萃取條件。研究進一步證實：不同龍眼核粉末及萃取液之比例，以固液比1比10為最適添加比例。在上述最適萃取條件下，可回收鞣花酸及鞣花單寧，分別達60 mg/L與138 mg/L。在微生物發酵方面，以龍眼核萃取物、單寧酸、葡萄糖、蔗糖、麥芽糖及澱粉發酵生產鞣花酸，A. niger皆會利用生長，但A. niger只有以龍眼核萃取物或單寧酸作為碳源時才能生產鞣花酸，分別有25 mg/L及22 mg/L，另外以固態發酵的方式生產鞣花酸發現鞣花酸會慢慢的累積，60 g/L於第四天時鞣花酸可達最大濃度300 mg/L，在鞣花酸之生產方面，龍眼核粉末為一良好的基質。在單寧酶活性上若以龍眼核萃取物做為碳源，於70 g/L時有最大活性0.93 U/ml；若以龍眼核粉末做為基質，80 g/L於第三天的時候達最高活性1.04 U/ml，40 g/L及60 g/L於第六天時仍在上升。

關鍵字

鞣花酸 ； 鞣花單寧 ； 龍眼核 ； 萃取 ； 微生物降解

並列摘要

Ellagic acid (EA) is a naturally occurring phenolic compound existing in many plants. Ellagic acid was a potential whitening, antioxidative, anticarcinogenic, antimutagenic and anti-inflammatory activities, and shown good prospects in cosmetic and pharmaceutical applications. Plant can generate autologous ellagic acid and transformed for ellagitinnin, gallic acid or other derivatives. Hence, it can be directly extracted ellagic acid from plants, or first extracted from the ellagitannin, reuse of transformation to produce ellagic acid.
Longan is a subtropical fruit, which is widely grown in China, Thaland and Taiwan, where half of the longan for fresh and the other longan to the core processing can be made guiyuan. As fresh or guiyuan food manufacturing process will produce large amounts of longon seed, longon seed will be discarded as agricultural waste. Literature suggests, Longan contains a lot of plant polyphenolic compounds such as ellagic acid, ellagic tannin and gallic acid. The aims of this study will take the advantage of this waste to produce ellagic acid, would be consistent with the waste recycling and improve its economic benefits of a dual purpose.
Firstly, we study the different extraction methods to recovery of ellagic acid from longan, and then with the microbial transformation will be extracted from ellagitannin into ellagic acid. The result shows the best extraction condition was 50% ethanol solvent to extraction. The study further confirmed that different of longan powder and extraction solution ratio was solid-liquid ratio 1:10 for the optimal conditions. Above the optimum extraction conditions were 60 mg / L of recyclable ellagic acid and 138 mg / L of ellagitannin, respectively. In microbial fermentation, the use of longan extract, tannic acid, glucose, sucrose, maltose and starch to fermentation production of ellagic acid. A. niger both to use growth, but A. niger only longan extract or tannic acid as a carbon source to produce ellagic acid, respectively, 25 mg / L and 22 mg / L. The other terms of solid-state fermentation production the ellagic acid will slowly cumulative, and use 60 g / L longan powder on the fourth day can reach the maximum concentration of 300 mg / L. The tannase activity if the longan seed extract as a carbon source at 70 g / L when the maximal activity of 0.93 U / ml, terms of longan seed powder as a matrix of 80 g / L on the third day whenthe highest activity of 1.04 U / ml, 40 g / L and 60 g / L on the sixth day is still rising. The longan powder is a good matrix on ellagic acid production.

並列關鍵字

Ellagic acid ； ellagitinnin ； longan ； extraction ； microbial degradation

參考文獻

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